Advice on coolant flush/heater hose inlet hose? 92SE

[92SEPathFindr]

Hi friends, I'm new to Pathfinders and hope to get a bit of help. My radiator fluid/coolant is rusty colored. I want to flush the system well a few times with some of the flush products before I refill it with antifreeze & distilled h2o. In 2011 there was quite a bit of work done including engine, water pump, all hoses, clutch, and more and I assume the thermostat. I bought a Prestone Flush kit which includes the Tee fitting. I don't have a FSM yet and there is a lot of different advice about how best to do this and not necessarily for my year Pathfinder. Any help? Thanks! I have a photo of the heater hoses coming through the firewall and I want to find which one is the "heater inlet hose". My kit says to put the Tee in that hose. Cheers and thanks a lot.

http://s304.photobucket.com/user/ut234/library/1992%20Pathfinder%20SE

[92SEPathFindr]

http://www.nissanpathfinders.net/forum/topic/41514-hello-npora/?p=772827

[92SEPathFindr]

After looking into quite a bit I was planning to follow the Prestone directions (sort of): Remove & clean overflow reservoir and leave it unhooked until finished flushing. Drain radiator, put the Tee in the heater hose inlet hose, close radiator drain, add the cooling system cleaner & water and run engine for 10 minutes (or more), then hook garden hose to Tee and put splash deflector tube in radiator opening and run engine while flushing the system with the hose-water until the water runs clear. Then I thought I would do the process a second or even a third time. Then after reconnecting the overflow reservoir, add 60/40 mix coolant/distilled h2o until full and I was planning on opening that bleed bolt on the top intake Plenum to let the air completely out of the system. My questions:

1) Which hose of the two hoses is the "heater inlet hose"? Top hose or bottom? My photos show the hoses.

2) Do the engine block drains need to be opened? There are two correct?

3) Does the thermostat have to be removed?

4) Anything you would do differently or recommend also doing? Thanks again!

[92SEPathFindr]

Any thoughts/advice? Thanks a lot.

[Steve_RI]

I tapped the top hose with the Prestone kit. I would drain all the coolant you can first - radiator and block. Then flush it good, drain and repeat. I think I blew the heater core out when I did this way back when (2005), but I don't think that is necessary, but it sound like you might need to flush the heater core separately given your issue. I never messed with the thermostat with the flush. It's a PITA to get to. Might as well do the timing belt if you go that route.

 

 

[92SEPathFindr]

I Appreciate the feedback Steve. Thank you.

[Terranovation]

When I did my flush I drained the old coolant out, remove and scrub out overflow reservoir, then with the rad cap off I stuck the garden hose into the bottom drain **** of the radiator to reverse flush it. I could see little bits of green coolant still mixed with plain water. Then with the hose still running, start the engine and put the heater on hot with fan speed on high. This was to open the valves on the heater core. I ran it for five mins, then turned the hose off and removed it from the drain hole. Lots more brown colored water came out. I did this a few times until the water was clean. I didn't use any radiator flush either.

[92SEPathFindr]

Thanks for your information Old-Timer! I am thinking about a way to recirculate the water plus flush product(s) so that I can filter out particles (with a very fine large screen I have) and maintain the water hot enough to open the thermostat while doing this repeatedly maybe with different products. A career mechanic I know said put some Tide laundry powder in with the radiator water, run the car for 5 minutes then drain, repeat until cleaned, then flush with clean water, then add coolant/distilled mix, etc. He also said doing it this way I would NOT need to remove the thermostat. Another online thread recommended Formula 88. http://www.homedepot.com/p/Formula-88-All-Purpose-Cleaner-and-Degreaser-128-oz-04312/100145974?cm_mmc=Shopping|THD|G|0|G-BASE-PLA|&gclid=CjwKEAiAmNW2BRDL4KqS3vmqgUESJABiiwDTODN_MIYGzf7lyKcJ6W877rIDwceGsMuVGh1OtowdeBoCcE3w_wcB&gclsrc=aw.ds

 

Any other cooling flush knowledge? Thanks

Edited March 1, 2016 by 92SEPathFindr

[92SEPathFindr]

Does anyone have the FSM picture with how the coolant flows through the engine, radiator, and heater and can you link to it or post it here? Thanks

[Slartibartfast]

http://www.nicoclub.com/FSM/Pathfinder/Download the '95 manual and look in the LC section.

 

A mechanic I know told me he's had trouble with those T-fittings getting brittle. A friend of mine used one on his van with no issues so far. I can see using it on the van (where the working room in the engine bay is a cruel joke at the owner's expense) but I'm not sure I understand the benefits of it otherwise.

[silverton]

There are no valves in the heater core. Coolant is always running through them. Always. Yes, even when your stick is on full cold!

 

I've done this on several different vehicles and I've always done in the same way. T in the inlet heater hose (that's the top one on pathfinders). Drain radiator. Connect hose to T and turn it on. Wait for water to come out the coolant cap neck. Start engine and wait. It'll be dirty, and then it'll get clear, and then dirty again, and then clear. Done. I even like to give the throttle a bump here and there to expedite the process, it doesn't take long as the coolant system is only a couple gallons.

 

They have you T in the inlet hose on the heater core so the hose water hits the heater core first. The water pump is directing flow and there is a bypass around the thermostat (there has to be), but it will eventually open partially and allow more dirt flow, that's why it gets dirty again!

 

If it doesn't stay clean when you put coolant/h20 in, then you have other issues. More than likely the water pump or the radiator being ran with plain water for too long, only fixing is replacement. Hopefully the flush sorts you out.

[92SEPathFindr]

Great, thanks for the help Slartibartflast and silverton. I have used the Prestone Tee on my Subaru over 10 years ago and the Tee has held up great with a few flushes since. I plan on doing basically what you described. I haven't done this yet and was looking to get feedback beforehand.

1) Not necessary to open the two block drain bolts right?

2) On refilling I will need to use that bleeder bolt (driver's side toward the rear with the sticker that says only open while cold) to get all the air out correct?

3) I've read about others using baking soda, or Tide powdered detergent, or something called Formula 88 for the flushing process. Anyone ever used CLR, (Calcium, Lime, Rust)? Thanks for the tips. Aaron

 

 

[Steve_RI]

#1, not necessary, but I usually try to drain as much of the old coolant out first and recycle. Plus, after flushing, you get most of the water out for refill..

#2. you can also just raise the front end up a bit and bleed it via the rad cap.

#3. I have only used coolant flushes in the past, so not much to offer here.

[92SEPathFindr]

Thanks Steve_RI! Anyone replaced that miserable drain on the radiator with a valve or something that opens and closes more efficiently? Or maybe the bottom of my radiator is full of debris? I don't know but the drain seems horribly slow and restricted. Thanks again for the help!

[Steve_RI]

These radiators are pretty easy to remove. If you feel you need to replace it, I went with a cheap Rockauto (Spectra), which is adequate IMO.

[92SEPathFindr]

Update: I drained the system/radiator, filled with Prestone Flush and then hose water, ran it for 30 minutes+/-. Drained it, added powdered Tide (whole tiny box from laundromat) after dissolving it in hot water (recommended by a career mechanic I know), ran it and drove it for 30 minutes+/-. Cleaned the reservoir overflow with hot water, dish soap, and added white rice to scour the inside clean and that worked well. And that's it so far. When I removed the battery I found two, stripped from abrasion, wires? Here are photos of the progress and the wires:

 

[92SEPathFindr]

Found a cool video on the coolant system:

[Slartibartfast]

That looks like your fog light harness. Probably easiest to just scab in some new wire where it's damaged.

 

I can see why you wanted to flush it now! That's nasty in there. I hadn't heard of the rice trick, I just used a handful of gravel when I cleaned out my overflow.

[92SEPathFindr]

That looks like your fog light harness. Probably easiest to just scab in some new wire where it's damaged.

 

I can see why you wanted to flush it now! That's nasty in there. I hadn't heard of the rice trick, I just used a handful of gravel when I cleaned out my overflow.

 

Yes, it was rusty, rusty water with a lot of really fine rusty silt and I think just plain water no antifreeze. After draining I added another dissolved box of Tide, ran it for 30 minutes, drained, then flushed with the Prestone Tee while the cap and radiator drain were off. Added another bottle of Prestone flush, drove it, drained and flushed with hose water. This time inadvertently I unscrewed the drain/plug completely out and it flowed out great. Flushing with the plug out really allowed good flushing! Now the system contains distilled h2o & Prestone flush/cleanser until the next flush. Then one more product "Thermocure Rust Remover" before I flush again & then add 60/40 antifeeze/distilled H2o is my plan.

Yeah, the rice trick works well and I added some dishwasher powder and dish soap.

 

My question is about the overflow reservoir as my previous vehicles didn't have this kind: After starting (when cold) does the radiator purge into the reservoir while heating and then suck it back out once the thermostat opens? Thanks!

[ahardb0dy]

I just filled the system with the flush and water, let it warm up to op. temp, than drained the radiator, repeated about 3 more times and refilled with anti freeze.

 

Make sure to remove the air bleed screw located on the side of the intake manifold when doing your final fill, after you get a steady stream of coolant coming out, put the screw back in,

 

and also make sure to have the heat on so the coolant will circulate through the heater core.

[92SEPathFindr]

Thanks ahardb0dy, I learned about the bleed bolt. Very nice feature! I think the need of a more aggressive flush depends on the condition of the cooling system. In my case, the Tee cut into the heater intake hose really helps to flush the entire system with hose pressure. I'm very satisfied with the results and I will be flushing it twice more before the final refilling. My heater works well with good fan power and my temp gauge, once warm, stays pegged right about 1/4.

I don't have a FSM yet but the owner's manual states to fill the overflow reservoir to the "Max" line when refilling the system. After cleaning, I replaced the tubes in and out of the reservoir, yet I am uncertain as to what is it's function aside from being just an overflow reservoir.

My question is about the overflow reservoir. After starting (when cold) does the radiator purge into the reservoir while heating and then suck it back out once the thermostat opens? Cheers and thanks for feedback everyone!

[ahardb0dy]

You can download the manual for the 93,94 or 95 as they are all very close to your 92.

 

http://www.nicoclub.com/archives/nissan-pathfinder-factory-service-manuals.html

 

I thought there was only one hose going to the over flow bottle ?

 

The coolant flows to the overflow when it has too and the engine draws it back when it needs it, I do not think it is an everyday every time the engine is running thing, usually if the engine gets to hot (overheats it will pull fluid in.

[PathyAndTheJets]

The radiator cap is designed to hold about 13 lbs of pressure. More than that and the spring compresses and vents excess fluid into the overflow. Pressure is caused by heat, so when it cools off the cap allows the coolant to be pulled back in from the overflow.

 

Older cars used to just let it spill on the ground and you'd just need to top it off occasionally.

 

I'm not sure if the 90-95s have the bleeder tee in the upper rad hose, but I've had good luck topping off the coolant with that to get the air out. Didn't require a system bleed the last time I did it.

 

If you haven't gotten a new radiator cap yet, I recommend it. The seal is going to be covered in that rusty junk.

Edited March 7, 2016 by PathyAndTheJets

[silverton]

Holy! With that must rust colored junk in the radiator I'd just opt to replace it! It'll make the whole cooling system much more efficient.

[92SEPathFindr]

Thank all!! ahardb0dy, thanks for the link and there is one "to" hose, one "overflow", & one "inner" hose. I replaced the overflow (looked horrible) and the inner (was loose) and cut off 2 inches of the "to" hose (because it was loose). After thinking it over, I think we need to fill the overflow reservoir to the "Max Line" because that creates an existing vacuum/siphon situation. Then when/if there is an overheat, fluid flows in and create and because there's fluid already there it creates a siphon effect and when the pressure reverses the fluid is sucked back into the radiator. My overall point is OVERHEATING IS NOT ACCEPTABLE ..LOL and indicates big problems aside from a burst hose.

 

PathyAndTheJets, thanks and yes I did get a new 13lb cap from Pep Boys ($7/made in Mexico). The old cap was original equipment (26 years) and the rubber was bad and decaying. There is no bleed tee that I see. But that bleeder bolt on the manifold is GREAT!

 

Yes silverton, I know what you mean but that corruption is throughout the entire system including all the passages inside the engine, the heater core, the hoses, and the radiator. Total and thorough flushing is required to clean a contaminated system from what I have just learned. If the system is maintained and functional that's great but mine was contaminated. Now, I have flushed the system 5 times (3 Prestone/2 Tide powder dissolved) and just added this kick-ass product, Thermocure, for a few days and then I will flush again before the final filling with antifreeze & distilled H2o.

Here's some photos of the product and from today of my new to me Pathfinder. Thanks for the advice and help everyone!! All the best, Aaron