Coolant Problem. Head Gasket? Wd21

[porsche4786]

I have been trying to get a little help/ideas from another forum and haven't had much luck in the past couple weeks. And starting to get frustrated with this pathfinder I just purchased about 700 miles ago. I hate getting lied to about problems...I'm going to post the other info I posted on the other forum and see what we can find out. I'm leaning towards a cracked block or head gasket. But others I have talked to don't think it's that. But they also have no ideas as to what.

 

Feb 12th, 2010, 12:38 PM

I recently bought a 1990 Pathfinder SE last Saturday morning. And am having trouble determining if it has a blown head gasket or what. I replaced the valve cover gaskets the same and following day (after I purchased it, took me a day and a half to do the job). Got it all back together, started it up, and I had a pinch in a coolant hose in the rear of the engine (coolant was spraying out). So i went and got a new hose, replaced it and all was fine. I topped off the coolant reservoir and radiator. A couple days later the coolant reservoir was near empty. So I refilled it at work. I went home after work, back to work the next day, from work I drove about 20 miles to a u pull it. Drove back home, about another 20 miles, then after I was home for a while, another 8 miles. Drove to work the next day, coolant reservoir was still full. I drove home, and back to work the next day and the reservoir was half full. I'm not sure where it's going. Maybe a bubble in the cooling system and it's filling it up. There is no coolant in the oil, oil in the coolant, and the coolant doesn't smell like exhaust. It does have steam come out of the tail pipe after start up. Even if the engine is warm during start up (but it hasn't been above about 45 degrees out). When the engine is cold it steams more than if it's already warmed up. But if you drive it, it stops steaming. I have smelt the exhaust, and it doesn't smell like coolant to me. But I have a pretty bad sense of smell. Any ideas? My main thought is that there were/are air bubbles in the cooling system, either from before I got the truck, or while I had it all apart/when it started up and was spraying coolant out from the hose that was pinched.

 

Edit: There are also no leaks that I have seen. Nothing on the ground after it's been sitting. And it passed emissions the day I bought it.

Edit #2: I got a block tester and it didn't show exhaust in the coolant.

 

Feb 18th, 2010, 12:12 PM

I looked at the radiator, and in the upper drivers side corner it has a very small leak. It's hidden under the fan shroud, and there is dried/corroded coolant on the fins. I got a new radiator and replaced it last night. Hopefully that was it! Only thing I don't like is the new radiator is plastic, the old one was brass. But I guess for $80, new, I can't complain too much...Just gotta get myself pumped up for doing my timing belt in a couple weeks...

 

No coolant was hitting the ground or the skid plate. It was drying up before dripping off the radiator.

 

Feb 24th, 2010, 08:50 AM

Ok, It's been about a week since I replaced the radiator now. And I've added coolant to the overflow tank twice. And now it's half full when warm and closer to the low line when cold. How long does it take to get the air out of the system? Or do I have another leak somewhere...? I'm going to get a pressure tester tonight and see what kind of results I get.

 

Feb 25th

Added coolant yesterday at work and drove it home along with a few errands on the way home. I pressure tested it last night, and I am definitely losing pressure. I checked the oil (it has been about a week or so since I last checked it). And the dipstick had nothing on it. I got in the car and the engine was cold. And the coolant level on the full mark still. I went to fred meyer to get oil, poured in a quart in the parking lot and drove it home. The next morning (today) the coolant level was half full and the oil only half way up the dipstick. So I added another half quart. It's only been 700 miles since the oil was replaced. Coolant in the radiator and overflow are still nice and green. The valve covers have some seepage appearing, so I tightened the screws a little more. I replaced the valve cover gaskets a few weeks or so ago. Maybe I used the wrong permatex with the gasket. I should have probably used high temp permatex and not the regular. But no oil leaks that have appeared yet, and no coolant leaks that I can see. Getting frustrated. Half tempted to get a re manufactured engine. But that's a lot of work and money.

 

0 mins 13psi

2.5mins 12psi

5 mins 11.5psi

10mins 10.5-11psi

15mins 9.5psi

18mins 9psi

20mins 9psi

40mins 7-7.5psi

 

Thank you for your help

Edited February 25, 2010 by porsche4786

[ac92pathfinder]

hmm might be a head gasket issue or it can me a leak along the engine somewhere. someone here will reply very quick. this is the best site to get info.

[k9sar]

Personally, I never trust the overflow tank for diagnostic purposes. As far as pressure... it definately sounds like a small leak. IF you are not leaving a puddle or any ground indications, and you are blowing a little steam, it COULD be a small head gasket leak between the cylinder and the water jacket. I would expect to see foaming or darkening of the coolant if you are having leakage of hot gasses into the coolant but that could be hidden by the constant addition of coolant. With a small leak, you could throw in some radiator stop-leak and cross your fingers. One way to possibly tell if you have coolant seepage into the cylinder is to pull your spark plugs. Typically, a spark plug is a bit dirty with carbon. If you have one that is 'steam cleaned', you might have your indicator without tearing into the heads. I'll post more as I think of things and I'm sure others will also chime in.

[GrimGreg]

Look closely around the timing cover area, there are 2 common leak points around there if the parts are getting old. The small bypass hose above the thermostat, when it leaks it is hard to see. The other is the water pump, if it has gone bad, it has a weep hole on the bottom that will leak out fluid a drop at a time.

 

When I had coolent loss, it turned out to be my water pump.

[porsche4786]

Personally, I never trust the overflow tank for diagnostic purposes. As far as pressure... it definately sounds like a small leak. IF you are not leaving a puddle or any ground indications, and you are blowing a little steam, it COULD be a small head gasket leak between the cylinder and the water jacket. I would expect to see foaming or darkening of the coolant if you are having leakage of hot gasses into the coolant but that could be hidden by the constant addition of coolant. With a small leak, you could throw in some radiator stop-leak and cross your fingers. One way to possibly tell if you have coolant seepage into the cylinder is to pull your spark plugs. Typically, a spark plug is a bit dirty with carbon. If you have one that is 'steam cleaned', you might have your indicator without tearing into the heads. I'll post more as I think of things and I'm sure others will also chime in.

 

Thanks for the reply. No puddles on the ground. And I park it in my garage, so it would definitely be noticeable if it was leaking onto the ground. The steam that comes out is only when you start it up (cold or after it's been sitting for maybe 15 mins after driving it). Then once you drive for a mile or two, it stops. It may stop quicker if it's already warmed up. They make some products that are more for head gaskets. Some by Bars Leak, and another called steel seal. I pulled and replaced the spark plugs when I bought the thing and they were all the same looking, they all looked light gray or white. I pulled one of them yesterday and it looked like the old ones did for the most part. I got a compression tester and forgot to bring it to work with me, so I'll have to do that tonight. I was pretty tempted to try the head gasket repair stuff you pour into your system, but I'm not sure if it would clog any other passages. I've heard people talk both ways about the stuff. My grandpa used to rebuild (up to about 6 months ago) antique car engines and he said he used bars leak quiet a few times in the past (not with customers cars, with his own) and it worked without problems, but others say it clogged their radiator (which i just replaced) or their heater core.

[porsche4786]

Look closely around the timing cover area, there are 2 common leak points around there if the parts are getting old. The small bypass hose above the thermostat, when it leaks it is hard to see. The other is the water pump, if it has gone bad, it has a weep hole on the bottom that will leak out fluid a drop at a time.

 

When I had coolent loss, it turned out to be my water pump.

 

I've had quite the bad luck as far as water pumps in the past with my rx-7, I've replaced it on average once a year for 6 years, and I don't over tighten my belts. So that's the first thing I usually look at. I pulled the A/C tensioner pulley bracket off so I could see more around the water pump and thermostat. It's bone dry as far as I can see around the thermostat, water pump, and the coolant bypass hose. But wouldn't that also leave a leak on the ground?

 

I wish I knew about this problem when I took the valve covers off, because I would have just done the whole job. Instead of doing things over again. I planned on doing the timing belt this weekend, but now I put that off till I can figure out what this problem is. I guess I should have driven it for a while before jumping in and doing the valve covers right off the bat.

Edited February 26, 2010 by porsche4786

[Kingman]

My suggestion to you to find out 100% if it's a head gasket, is to take it in to a trusted shop and have them perform a head gasket test through the cooling system. What they will do is take a vial of some chemical that is normally blue, but will turn instantly yellow if any exhaust gasses are present in the system, and place it in the radiator inlet and run the engine. You can buy the same stuff from NAPA for cheap, and do it yourself.

 

I had a coolant leak from th upper bypass hose, it didn't leak a drop of fluid on to the ground until the leak got very bad. It was a pain in the ass to diagnose and fix, but well worth it. I had the same symptoms you had.

 

Steam from the exhaust in the morning or after sitting for a while is completely normal, it's just water condensation being heated up and steamed off in the exhaust pipe.

[Dowser]

I'm with Grimgreg on this one. I had a 91 Pathfinder and thought for sure it was the Waterpump that was leaking. I was going to do the timing belt anyway so i did the waterpump at the same time. Turned out the leak was not from the water pump. It was the little tiny bypass hose that is a small 90 degree hose. it had a small tear in it and it was obviously sporatic on when i would lose fluid because i wasn't getting the fluid hot enough until I was driving it for a length of time. Now upon further investigation the fluid appears to be coming out of the Back side of the engine because when the bypass hose has a small leak it drips down into the center of the block and channels itself to the back then drips down there. of course some came out the front too which is why i originally thought it was the waterpump. As to not seeing any wetness around there, my guess is its hot enough to be drying that all up in that area cause i never found a leak spot on mine either. When you decide to do your timing belt make sure you do that too even if that's not the issue. there's no way to change that little bastard unless you rip it all down anyway. I'm willing to bet that's the problem personally.

 

Good luck

[porsche4786]

My suggestion to you to find out 100% if it's a head gasket, is to take it in to a trusted shop and have them perform a head gasket test through the cooling system. What they will do is take a vial of some chemical that is normally blue, but will turn instantly yellow if any exhaust gasses are present in the system, and place it in the radiator inlet and run the engine. You can buy the same stuff from NAPA for cheap, and do it yourself.

 

I had a coolant leak from th upper bypass hose, it didn't leak a drop of fluid on to the ground until the leak got very bad. It was a pain in the ass to diagnose and fix, but well worth it. I had the same symptoms you had.

 

Steam from the exhaust in the morning or after sitting for a while is completely normal, it's just water condensation being heated up and steamed off in the exhaust pipe.

 

 

I did the block test a week or two ago. With the blue fluid. It didn't change to yellow (or any other color). But I don't think that's showing you if it's 100% the head gasket or not.

[Kingman]

I did the block test a week or two ago. With the blue fluid. It didn't change to yellow (or any other color). But I don't think that's showing you if it's 100% the head gasket or not.

 

If there's a leak, the exhaust gasses will be pushed from the combustion chamber into the coolant. The pressure inside the combustion chamber is much higher than the pressure in the coolant system.

 

When I had the leak, there was no evidence. The heat from the engine would burn the coolant off before it could leak all the way down, basically when the thermostat opened and the coolant started flowing. The bypass hose is right above the thermostat, behind the timing belt cover. Usually there's a little crack where the wire clamps hold the hose on to the metal inlets. Once I tore it down, I could see a small residue trail from the hose down past the water pump.

Edited February 26, 2010 by Kingman

[porsche4786]

I'm with Grimgreg on this one. I had a 91 Pathfinder and thought for sure it was the Waterpump that was leaking. I was going to do the timing belt anyway so i did the waterpump at the same time. Turned out the leak was not from the water pump. It was the little tiny bypass hose that is a small 90 degree hose. it had a small tear in it and it was obviously sporatic on when i would lose fluid because i wasn't getting the fluid hot enough until I was driving it for a length of time. Now upon further investigation the fluid appears to be coming out of the Back side of the engine because when the bypass hose has a small leak it drips down into the center of the block and channels itself to the back then drips down there. of course some came out the front too which is why i originally thought it was the waterpump. As to not seeing any wetness around there, my guess is its hot enough to be drying that all up in that area cause i never found a leak spot on mine either. When you decide to do your timing belt make sure you do that too even if that's not the issue. there's no way to change that little bastard unless you rip it all down anyway. I'm willing to bet that's the problem personally.

 

Good luck

 

It could be that your right, that it's evaporating when hitting the block, so not showing any signs of anything. But I thought I'd see something, some kind of a clue if it was that. I think the compression test will tell me a lot. If they all come out to about the same, then it's probably not the head gasket...right? The only thing I don't have, and that I don't believe I can rent anywhere, is a leak down tester. Which shows how long it takes for the pressure to drop in a cylinder. You use compressed air, it would show if you have a bad or small leak in your cylinders. I don't know of any reputable shops as far as pistons engines. I've only taken my rx7 to a shop recommended by a highly reputable rotary engine rebuilder. And I got it back with many problems, broken bolts, etc. He's now out of business. So I have a hard time trusting anybody working on my vehicles.

[porsche4786]

If there's a leak, the exhaust gasses will be pushed from the combustion chamber into the coolant. The pressure inside the combustion chamber is much higher than the pressure in the coolant system.

 

When I had the leak, there was no evidence. The heat from the engine would burn the coolant off before it could leak all the way down, basically when the thermostat opened and the coolant started flowing. The bypass hose is right above the thermostat, behind the timing belt cover. Usually there's a little crack where the wire clamps hold the hose on to the metal inlets. Once I tore it down, I could see a small residue trail from the hose down past the water pump.

 

Is it possible to have a head gasket leak and not getting exhaust in your coolant?

[GrimGreg]

Is it possible to have a head gasket leak and not getting exhaust in your coolant?

Yes, but usually it will run poorly no matter where it blows. Unlike Chevys, our head gaskets rarely go. Don't rely on a compression test, you could have worn valve seals or piston rings giving you a low compression reading also.

[porsche4786]

Yes, but usually it will run poorly no matter where it blows. Unlike Chevys, our head gaskets rarely go. Don't rely on a compression test, you could have worn valve seals or piston rings giving you a low compression reading also.

 

As far as I can tell it runs fine, sounds smooth, doesn't feel like it's got a loss of power. And no check engine light or anything. It's only got 146k miles. Which on a pathfinder I would consider low. Lets say you were getting coolant in a cylinder, wouldn't it feel like it's missing when you drive it?

[Kingman]

Sometimes, depends on how much coolant is getting into the cylinders. Leaking and blown are different things... You can drive around for a long time with a leaking gasket that's only letting small amount of coolant into the cylinders, not really affecting anything. Once it completely blows and dumps mass amounts of coolant in is when things really go down hill, and fast...

 

My step dad's Tahoe has a leaking head gasket that's been leaking for well over a year now, coolant in the oil and visa versa. It steams a hell of a lot, but gets just as good of gas mileage, runs just as smooth as before, and has the same amount of power. Without looking at the oil or coolant level you'd never know.

 

 

[porsche4786]

Sometimes, depends on how much coolant is getting into the cylinders. Leaking and blown are different things... You can drive around for a long time with a leaking gasket that's only letting small amount of coolant into the cylinders, not really affecting anything. Once it completely blows and dumps mass amounts of coolant in is when things really go down hill, and fast...

 

My step dad's Tahoe has a leaking head gasket that's been leaking for well over a year now, coolant in the oil and visa versa. It steams a hell of a lot, but gets just as good of gas mileage, runs just as smooth as before, and has the same amount of power. Without looking at the oil or coolant level you'd never know.

 

Does it ever stop steaming? Or is it always?

[Kingman]

It steams all the time. Theoretically if you had a blown headgasket it should steam more when it's warmed up since coolant is flowing throughout the system.

[long]

Since reading all of this im gald ive got a TD 2.7T this way it may not have the grunt of a V6 but hang it sure has the torque when needed.

If its of any use i have the V6 service manual here on CD pm me with a google e mail addy if you would like a copy of it.

I said a google account because they will accept e mails of up to 10 gig with no worrys 99% of other accounts just bounce it..

Edited February 27, 2010 by long

[porsche4786]

Ok, I just did a compression test and they all read very well, maybe off 5-10psi per cylinder. All above 150psi. I got a UV leak test kit, and will do that next...hopefully it shows up...

[5523Pathfinder]

How did your plugs look? If you are burning coolant, some traces should be present on the plugs. I would lean toward maybe a leak from a intake gasket or the bypass hose behind the timing covers. I would pressurize your cooling system and watch how long it takes to loose pressure and start looking for leaks. A good flashlight and a small mirror will help in the hard to see areas. Also, look underneath or any traces of green or white line down the sides or back of the engine.

[porsche4786]

How did your plugs look? If you are burning coolant, some traces should be present on the plugs. I would lean toward maybe a leak from a intake gasket or the bypass hose behind the timing covers. I would pressurize your cooling system and watch how long it takes to loose pressure and start looking for leaks. A good flashlight and a small mirror will help in the hard to see areas. Also, look underneath or any traces of green or white line down the sides or back of the engine.

 

The plugs look light gray-whiteish. I'm going to do the timing belt/water pump today along with the bypass hose. The timing belt needs to replaced, it's been about 60k miles as far as I can tell maybe a little more. Also...I didn't see any of the UV dye in the coolant anywhere. But this morning I was at my GF's house out in the country, and there was a little green in the puddle under the car. I shook the radiator drain hose and a couple drops came out of it. But I also had drained some coolant yesterday to put the dye in...

 

 

0 mins 13psi

2.5mins 12psi

5 mins 11.5psi

10mins 10.5-11psi

15mins 9.5psi

18mins 9psi

20mins 9psi

40mins 7-7.5psi

Edited February 28, 2010 by porsche4786

[porsche4786]

The plugs look light gray-whiteish. I'm going to do the timing belt/water pump today along with the bypass hose. The timing belt needs to replaced, it's been about 60k miles as far as I can tell maybe a little more. Also...I didn't see any of the UV dye in the coolant anywhere. But this morning I was at my GF's house out in the country, and there was a little green in the puddle under the car. I shook the radiator drain hose and a couple drops came out of it. But I also had drained some coolant yesterday to put the dye in...

 

 

0 mins 13psi

2.5mins 12psi

5 mins 11.5psi

10mins 10.5-11psi

15mins 9.5psi

18mins 9psi

20mins 9psi

40mins 7-7.5psi

 

 

I'm about done with the water pump job. But Fast Undercar sent me the wrong timing belt....so I didn't get to finish it last night. It was the belt for a newer pathfinder with rounded teeth, not squared. I got the coolant bypass hose on without removing the rear timing belt cover, I removed the distributor to get more access to the hose (still wasn't easy getting the hose on). I wasn't comfortable trying to get the camshaft pulleys off (afraid of spinning them). There was a decent amount of rust under the water pump, but no sign of coolant. Just oily, looks like possibly the main front seal, so I replaced it. Hopefully the rest of the job goes well and it fixes the problem.

[porsche4786]

I'm about done with the water pump job. But Fast Undercar sent me the wrong timing belt....so I didn't get to finish it last night. It was the belt for a newer pathfinder with rounded teeth, not squared. I got the coolant bypass hose on without removing the rear timing belt cover, I removed the distributor to get more access to the hose (still wasn't easy getting the hose on). I wasn't comfortable trying to get the camshaft pulleys off (afraid of spinning them). There was a decent amount of rust under the water pump, but no sign of coolant. Just oily, looks like possibly the main front seal, so I replaced it. Hopefully the rest of the job goes well and it fixes the problem.

 

Ok, water pump/timing belt/tensioner/crankshaft seal/ and thermostat are done. The engine temp gauge doesn't seem to go as far up as it used to. The picture is how far it goes while driving on pretty flat land. And it went a little higher when I was driving over the hill this morning. The red line is where it used to get up to, and the green is what it got up to today going over the hill.

 

[GrimGreg]

Did you make sure to bleed out all the air this time around? What does the temp hit if you let it idle for about 15 minutes?

[porsche4786]

Did you make sure to bleed out all the air this time around? What does the temp hit if you let it idle for about 15 minutes?

 

Pretty much where it is right there. I had to mess with the timing for a while (didn't mark the distributor) and I had the radiator cap off while doing that. Hopefully it found it's way out. But I don't think that was the problem last time. May even be a tad less than that after 15 minutes.

Edited March 2, 2010 by porsche4786