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Blown/Seeping Head Gasket?


onespiritbrain
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I sure do and in approximately 10 hours I will take it apart and post pictures. I am interested to see what the trans cooler portion looks like.

 

I’ll also try to figure out what brand it is since I don’t think I saw the Nissan symbol on it anywhere but I guess they all use basically the exact same design.

 

 

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  • 3 months later...

I am still loosing coolant and I think it’s either a BHG or a cracked head...

 

*I lose about half a gallon per 100-150 miles and I have zero leaks and zero sweet smells.*

 

I do have slow bubbling in the reservoir after short/long drives above 90degF ambient.

 

With the radiator completely full and at idle the coolant temp slowly creeps up to 225degF+.

 

I want to do the right thing and make the repair, after compression checks and everything of course, but I am discouraged because I also believe the bottom end needs new bearings, mains and rods..

 

By the time I get HGs on with milling and replace all the bearings I am going to be above the cost of another JY motor... I also don’t want to mess with having the crank turned so I’d be slapping standard bearings on and hoping for the best.....

 

And so... I am slightly inclined to just pour a block/HG sealer in and hope for the best, try to get enough time until my wife finishes school and I can afford better options.

 

Opinions on what you’d do in this situation are welcomed..

 

 

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I’ve decided against doing the bearings since I’d have to pull the engine.. I’m just going to tear into these head gaskets.

I’ll have to get my other car back up to speed.. it’s infiltrated by spiders and wasps, needs a trans flush, and an AC service.

Hopefully I’ll be able to order the parts this Friday. Wooh! I’m trying to get pumped about all of this haha.. I’ll keep y’all posted.


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Well I just performed a leak down test which it passed.... bittersweet because I was honestly relieved by my previous confidence in a blown head gasket. I’m ready to get this behind me.

 

This car is going to stay with me forever. I don’t care how big a pain any of it is, it’s staying. I bought it with the small inheritance my dad left me, and I also fixed the transmission and engine with that same money, so it’s like a piece of him here with me..

 

I want to get this disappearing coolant and the following overheating condition taken care of now.

 

I am going to do the Taurus electric fan conversion but this missing coolant thing has got to stop first.

 

I am wondering about the intake plenum now.. I looked inside the throttle body and it was just black and sooty. My oil level does not rise, however, it was previously using more oil than it does now and I’m wondering if the missing oil is being offset by the introduction of coolant. And also since the water intrusion is so slow maybe it is falling out of oil suspension, evaporating, and being burned by the PCV function. I do have snot on the oil cap.. I don’t know anymore....

 

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I already sold my bow, which I also bought with my inheritance, so shame on me for not doing this test first...

 

Here are the spark plugs in order of; 1, 3, 5, 6, 2, and 4. I accidentally skipped 4 and did 2 first. Also I cleaned the number 2 plug before I took the picture. It looked just like 4 except the threads were wet with what looked like oil..

 

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Here is this leak down test that I made:

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I set the pressure on a high precision regulator here at work and measured the leak rate. More than anything I wanted to put 200psi on the cylinders and watch for bubbles at the filler neck on the radiator. No dice...

 

I did find that cylinder number 2’s exhaust valve didn’t seat right with the gentle opening and closing of rotating the crank shaft..

 

I guess the next step is to pressurize the cooling system and look for external leaks... I guess it might be good to send an oil sample to Blackstone to see if they detect coolant in the oil. I guess I will also add a dye to the coolant and all that as well..

 

Any advice is much appreciated. I will try whatever y’all tell me.

 

 

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The bubbles coming out of your radiator suggest that combustion is leaking into the coolant, and the pudding in the cap suggests coolant's getting into the oil as well (though I have heard of some cars developing similar schmoo from doing mostly short trips and never warming up properly). Odd that the plugs look about the same and the leakdown test didn't pin anything down, though. Maybe the leak only opens up when the engine is warm?

 

You can test the coolant for hydrocarbons to confirm that the bubbles are exhaust gas. You can also heat up a little oil (just a drop from the dipstick) on a piece of foil with a lighter to test for water. If it just gets hot and smokes, it's just oil; if it sizzles and pops like when you drip water into hot bacon grease, there's water in there.

 

 

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You need to get it tested for hydrocarbons like Slartibartfast suggested. I have one of these testers and it is very easy to use. It will tell you right away if you have a head gasket leak, even if it is a very small leak. You just lower the level a little in the radiator so the tester doesn't suck up coolant, put a dye in the tester and then place it in the radiator neck and pump the bulb. The tester will draw air from the radiator and pass it through the dye. If hydrocarbons are present the dye will change from blue to yellow. Super easy! If you were local I'd test it for you.

James

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I rented the block tester(prt# 27145) from autozone and ran the test for over 10min at 185degF and it was just as crystal blue at the end as it was at the beginning... at one point there was even bubbles coming up through the tester from the coolant system without my assistance from the suction bulb; zero color change whatsoever..

 

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*after 10mins*

 

I did the foil test and I found that both new 5w30 and my engine oil bubble and sizzle right before burning up. I think I would need a hot plate that I could control the temperature on to tell if my engine oil bubbled any differently than the new oil.

 

However, by eye it seemed like the new oil resisted burning up about twice as well as my engine oil. The new oil would “run away” from the flame and become quite thin before turning darker, bubbling, and burning up while my engine oil would quickly stick where it was, turn dark black, bubble, and burn up. I don’t think I am able to determine anything without better control over the test.

 

It is quite strange.. I was so sure it was a head gasket. I must be a more subjective thinker than I realized, of course that would be natural for a subjective thinker haha..

 

Anyways, I have an endoscope on order from Amazon that’ll be here on the 17th. I plan to check the inside of my cylinders in all sorts of situations. It’ll also help me to look for external coolant leaks. Speaking of.. I did find and fix this yesterday after the leak down test:

 

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That is the small coolant bypass hose behind the engine and between the two heater core hoses!

 

I can’t wait till this is over.. before I killed my previous engine I could start it and leave it running forever without worrying about it overheating.. every car I’ve ever owned I had to worry about it overheating, until this QX4.

 

 

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Well that confirmed you don't have combustion gasses getting into the cooling system then. I can't figure what else would let air into the cooling system. Possibly the water pump or a small leak on the suction side of the pump pulling in air when its running but I would think something like that would drip coolant when you shut it down. Good luck finding this problem, I'll be watching.

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I am wondering if that very small bypass hose leak slowly allowed the system to draw more and more coolant out of the reservoir bottle until it emptied the bottle and filled up with air. Then I panicked and filled the reservoir and radiator back up without burping all that air out and that’s why I saw it take a 1/2 gallon of water in 100 miles.


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My endoscope was waiting on me when I got home today so I got it going and started poking around with it... Looked at that little bypass hose and this is what I found!

 

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Now this is after I already trimmed the hose back and put a new clamp on I know it’s not loose so I’m thinking maybe the hose is just deteriorated. Also the thing looks strange by how swollen it is just after the clamp.

 

The upper radiator hose, heater core hoses, and that bypass hose are all swollen.

 

These are all old hoses. They looked old when I bought this vehicle so I’m guessing they’re at least 100-120k miles old.

 

 

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yes i would replace that hose, it could be leaking between the layers. Make sure you get coolant hose and not fuel line also. Some parts people don't know there's a difference. If you can't find small coolant hose at a parts house check a big truck dealer.

James

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Odd that they're all swollen. I've replaced a few coolant hoses on my '93 but only because I was in there anyway. I've heard of coolant hoses going mushy from oil exposure but given that your HC test turned up negative and your coolant isn't scummy I doubt it's that, unless the PO did something dumb. Hopefully new hoses are all it needs and the bubbles and level drop are just due to refilling w/o burping.

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caca5bbd116e3ac264dbea3f59c60b75.jpg
Cylinder #1
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Cylinder #2
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Cylinder #3
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Cylinder #4
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Cylinder #5

I don’t see a significant difference in any of these. I will try to look into #6 tomorrow. I am still loosing coolant though.. I just really don’t want to rip the engine apart without being 100% sure it’s blown. I don’t see any coolant leaks anywhere still also.


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If a cylinder was leaking and coolant getting in, the piston will be cleaner than the rest. The dye test is usually pretty definite that there isn't a leak though. I think I'd try one of those little tubes of powdered stop leak next! That's the best way to stop small leaks that you can't find.

James

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I was saying “crap crap crap” before I even entered the chamber..
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#6 is quite noticeably cleaner than the rest...
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It kind of looks chewed up also..

You know, when I first started this engine it was knocking loud. I thought it was a rod bearing but now I think it was detonation. And that detonation probably compromised the head gasket. My guess is that the injector for that cylinder was probably not firing well and caused powerful lean detonations.

I’m glad the search is finally over... this has been a rollercoaster ride.



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I ordered my parts today and borrowed a car from my best friend. I’m ready to get this knocked out! My goal is to have everything done by next Saturday the 4th of August.

c8b00addacfabd8aa8c810de3d9d6a13.jpg
And so it begins..


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09854ea49b7a93949006453047e557c3.jpg
This guy was hanging out the whole time last night until he flew on my neck and I had to kill him..

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Made some serious headway last night with the short time I had to work. The upper intake is indeed a pain but without the hood and with long tools it wasn’t as bad I was anticipating. It’s that power steering tensioner you gotta watch out for..

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This was a complete shocker. When I put this engine in this area was dark red with varnish and contained thick hard sludge in the crevices. It is waaaaay cleaner than it was.. I am guessing this is from the synthetic oil??? Or water in the oil???

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Here’s where it’s at. Oh and those gloves right there, or any tight fit leather mechanic gloves like those, are an absolute must! For a bigger job the $20 they cost should be figured in. They made such a big difference last night. My hands were more of a tool themselves than just the part of me that uses a tool.

When I get home today I’ll post a side by side to show how much it cleaned up under those valve covers.

More to come.


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