I have a 98 GMC Sierra 3500HD with a 6.5TD and one heater hose is touching the turbo exhaust outlet. This area is hot as heck, I think someone changed the hose and it is:

1. Not ran properly and too close to the turbo exhaust.

2. Missing heat shields.

3.The wrong hose.

Anyone have advise on how to fix this? I need help on how the hoses should be routed and where to find the OEM or better heat shields or sleeves to protect the hoses.

Thanks,
Lou

Take a pic and post it so we can get a better idea of what you are talking about. A picture is worth a thousand words around here sometimes.

Tony

I can't get a picture of it, too tight of an area.

I'm not sure which one of the three conditions I listed is the problem, but a good parts/maintenance manual drawing would help.

Can anyone confirm if a heat shield or sleeve is near the hose at the turbo?

Thanks,
Lou

hey lou. what color is the hose? i know that sounds strange but it looks as if my truck has a green silicone hose in that area. i'm guessing because silicone hose can take more heat. its not touching the exhaust anywhere however. i don't have A/C in my truck so i can get a little better look than someone with A/C as the accumulator/dryer is right in the way.

The hose going to heater is green and has a metal end on the end that goes into quick connect on engine. Its bent properly from factory. Bad part is not sure GM still offers the hose its low frequency service part now. I just bought one a month ago and it came from another dealer stock not from parts distribution. Many like to use a pipe nipple instead of GM quick disconnect.

Also the hose back to radiator is prebent. There is a 3rd hose from the coolant expansion tank to radiator and I think that one has a silver backed insulation on it around the down pipe area not sure other have it.

It does get really hot under there. I found melted wire looming near my starter. I'd suggest looking through JEG's or Summit racing for some insulating foil backed tape. You can also google hose sleeve but the industrial stuff is pricey is why I suggested jegs or summit racing. Buy some new hose and route it best you can then protect it. Don't let it touch turbo, manifold, or down pipe. Get more hose than you need and zip tie it as necessary and loop it away.

I wonder if someone replaced it with a normal hose and not for the 3500HD? When I put the 3" body lift on my 94, I had to do some serious tweeking to that hose. I had to cut some off the end off(about 2", IIRC) and bend the aluminum pipe some.

IIRC there should be a metal heat shield covering the back of the turbo, held on with three little bolts.

The hose appears to be green but I saw a parts drawing on the GMPartsDirect site showing item #11 as a heat shield. Problem is, not available.

My truck does have A/C and the area is further complicated by that. The heater "hose" that runs from the engine looks like an A/C hose.(tube/hose combo.

This truck is my bucket truck which idles and high idles quite often, so keeping it at the right temp with no leaks is essential.

I suppose the safest thing to do would be to wrap the hose and the wiring harness in that area. I want to also rout the hoses properly when I find out exactly how they should be.

There is a hose clamp mounted to the frame near the front right wheel - Which hose should be in there?

Again, any drawings or photos showing the correct routing would be appreciated.

Thanks to all,
Lou
OIF 3 Vet
42 ID 1/150th GSAB
Bravo Company "Misfits" DARNG
(the Army guy in this thread will understand the above)

Hi guys-I just put the SS Diesel '97 cooling upgrade on my rig. After getting the whole thing buttoned up, the "quick couple" that leads from the heater aluminum tube to my crossover manifold is shooting coolant everywhere. It appears as if the plastic "release" buttons are completely gone/broken. Can I replace this part or do I need the entire aluminum tube unit? Also, does anyone know what the hell that part is called? Thanks for the help!

Also, why did GM use an aluminum tube for this and didn't just run plain ole heater hose? Can I use heater hose and scrap the aluminum tube?

It's an easy fix - pics are in my garage - kinda shows how to route the heater hose and get rid of the lame quick connects.

Also, why did GM use an aluminum tube for this and didn't just run plain ole heater hose? Can I use heater hose and scrap the aluminum tube?

For easy of assembly at the factory.....and to make sure you have good business at the stealership when the friggin things start to leak. Any auto part store should have the hose adapters (around 3-4 bucks) - then just put plain ole heater hose on. Like the pix in my garage.

NEVER replace that aluminum quick connect crap with the same OEM junk.

It's an easy fix - pics are in my garage - kinda shows how to route the heater hose and get rid of the lame quick connects.

Thanks Odlaw!! Did you use a simple hose coupler and hose clamps to connect it to the heater hose that runs to the heater core? The only picture I could find in your garage detailed the shut off valve. Great idea by the way.

Thanks Odlaw!! Did you use a simple hose coupler and hose clamps to connect it to the heater hose that runs to the heater core? The only picture I could find in your garage detailed the shut off valve. Great idea by the way.

Yes, I'm not at home right now but I have the napa part number for the hose adapter. Just screws right in where the OEM quick connect comes out(hopefully it will just unscrew - but usually breaks:mad:) then just slip the hose over the nipple and clamp her on.

Regarding the cut off valves, one of the 'old school' line of thinking is that you only need one valve because then it stops the circulation, but I can tell you from personal experience that the heater core will still get hot as the coolant will still mix somewhat and the temps will rise in the heater core. Put one valve on each side and it will stay cool. I don't know about other year models but my 92 the heater core is the last thing at the bottom of all the plastic duct work under the dash - slightly right of center and about 6 inches above the tranny hump on the floorboard - made a big difference on cooling my truck in the summer. Plus an added bonus, when the heater core does spring a leak - it's not a show stopper - just turn the valves off and keep driving. The valves I used are gas valves - much smaller and they're quarter turn valves.

I had that melted hose problem when I bought my last truck. The previous owner had left the a/c hose loose. I wrapped the new one in heat resistant fabric and covered that with aluminum tape, then tyewrapped it against the fenderwell. Problem solved.

[quote=odlaw;2832541]Yes, I'm not at home right now but I have the napa part number for the hose adapter. Just screws right in where the OEM quick connect comes out(hopefully it will just unscrew - but usually breaks:mad:) then just slip the hose over the nipple and clamp her on.

Thanks again. If you could come up with that part number, it would be much obliged and alleviate the guy at NAPA lookin' at me like I've got a dick growing out of my forehead when I try to explain it to him.

Doesn't the OEM quick connect have some kind of a restricter in there for proper flow?

I had that melted hose problem when I bought my last truck. The previous owner had left the a/c hose loose. I wrapped the new one in heat resistant fabric and covered that with aluminum tape, then tyewrapped it against the fenderwell. Problem solved.


That was a good idea! I will have to remember this for when my heater hose starts to act up.
Thanks,

I use a small valve with about a 1/4" passage on mine to kill 2 birds with 1 stone. Yes, the heater flow needs to be restricted. I just had to remove one of my crossovers to remove the broken off adapter. It looked good on the outside but was eroded on the inside to paper thin and just fell off before I could even put any pressure on it.

So without the resticter what happens?

I have read "heater core erosion".

It does not need to be restricted - the heater core handles that....maybe up yonder in colder country...I guess that might help but the restriction of the heater core itself does the job for me.
The only restriction I had on my OEM quick connect was corrosion! :rolleyes:

The restriction is to simply limit the amount of coolant that bypasses the cooling system (between engine and radiator).

If you go the nipple and hose route you can get a 6.2 nipple with the proper restriction, although many have used a barb with no restriction, doesn't seem to make any difference.

The coolant that goes to the heater core gets to the rad eventually, just has to travel a bit further.

see the little hose over the hose,
same thing on the heater hose under turbo and attached with 2 zip ties.

can post detailed pics later.....

http://buckner-engineering.com/private/automotive_forsale/Kommandofahrzeug/images/IMG_3976.jpg

I don't know about other year models but my 92 the heater core is the last thing at the bottom of all the plastic duct work under the dash - slightly right of center and about 6 inches above the tranny hump on the

Its easy to change, theres 5 IIRC screws going up from the bottom, take them out, two clips and undo your heater lines. About as easy as they come, hardest part is getting the hoses off.

Good thing its easy, my 92 went through somewhere around ten in two years. That restriction is important guy's. MY original went out shortly after my quickcoupler broke, I just stuck a regular hose nipple on there and didn't give it a second thought.

Well after a couple of each different manufacturer cores I could find, including two factory GM ones, I remembered that fitting I put in. I now have mine restricted down to 1/8" and all's well for the past 4-5 years or so.

You northern guy should probley run a 1/4" orfice, but I'm in north texas so the 1/8" works plenty good, usually only gets down in the 30's most of the time.

You can buy that plastic clip for the quick disconnect, there usually in th help section, next to the heater quick disconnects.

If you have a steel one already just replace the clip. If you have a pewter one, replace it with a steel one if your line and hose is still good.

The restriction is to simply limit the amount of coolant that bypasses the cooling system (between engine and radiator).

If you go the nipple and hose route you can get a 6.2 nipple with the proper restriction, although many have used a barb with no restriction, doesn't seem to make any difference.

The coolant that goes to the heater core gets to the rad eventually, just has to travel a bit further.

Most of this is without question, but I do need to point out one thing... there are many reports of leaking heater cores that all came from people who put their systems back together without the restriction...

Nobody has been able to prove that the lack of a restriction causes it, but the evidence is highly suggestive; enough so that we recommend that, rather than using a straight nipple, you replace the fitting with the steel one (including restriction) that can be bought at GM (http://www.dieselplace.com/forum/showpost.php?p=1832333&postcount=44). Part numbers are in the link... it costs like, $10.

Like I said, it isn't a guaranteed thing, but it's cheap insurance to use the right part... changing heater cores is a pain in the butt.

Most of this is without question, but I do need to point out one thing... there are many reports of leaking heater cores that all came from people who put their systems back together without the restriction...

Nobody has been able to prove that the lack of a restriction causes it, but the evidence is highly suggestive; enough so that we recommend that, rather than using a straight nipple, you replace the fitting with the steel one (including restriction) that can be bought at GM (http://www.dieselplace.com/forum/showpost.php?p=1832333&postcount=44). Part numbers are in the link... it costs like, $10.

Like I said, it isn't a guaranteed thing, but it's cheap insurance to use the right part... changing heater cores is a pain in the butt.

Well now, I don't know who to believe,
http://www.dieselplace.com/forum/showpost.php?p=959015&postcount=16
but I do believe to use the nipple with the proper restriction is indeed the right way to go...
http://www.dieselplace.com/forum/showpost.php?p=1468791&postcount=3

LOL... Nice quotes, CHB... like I said, I don't know for sure, either, but I figure on the off-chance the restriction IS necessary, $10 for the right part is pretty cheap insurance.

Have a good day, eh?

If you restrict it 1/8 or not at all the pressure in the heater core is going to be the same - just less flow if restricted - which should make for more heat.....

I don't think the restricting/not restricting has anything to do with the heater core leaking.

If you insist on having it restricted just tack weld a washer inside the nipple....

I think the leaking heater core is just because of crappy design....those swivel connections going into the core itself suck.

I had to laugh at those two opposite comments from GMCTD ...I don't care who you are, that's funny right there.

I had to laugh at those two opposite comments from GMCTD ...I don't care who you are, that's funny right there.

I never actually viewed them as opposite comments, only that the restriction in the heater core feed hose is a design feature intended to direct the bulk of the coolant flow in the engine cooling system, and that the restriction (or lack of) has nothing to do with leaking heater cores.

If one reads this (now horribly hijacked to kingdome come) thread from start to finish, it would be virtually impossible to distinguish fact from fiction, with regards to hoses, nipples, restrictions and such.

My intent was merely a (second) attempt to introduce some more-than-likely-to-be-factual information on the topic, from a respected source.

My own paraphrasing earlier fell somewhat short of the intended goal, I'm afraid.

If you restrict it 1/8 or not at all the pressure in the heater core is going to be the same - just less flow if restricted - which should make for more heat.....

Thats what I thought, just system pressure from the cap. But there is also the higher flow from these higher volume pumps used on the 6.2-6.5's as compared to gassers.

HMMWV's use the 1/4" restriction also, even though the coolant is returned to the pump enstead of the radiator. That would be a good mod for you northern guys, makes the heater heat up alot faster that way.

Some interesting reading.

http://www.carqueststores.com/common/downloads/partsTechTempcontrolCR331%20Heater%20Core%20Failur es%20and%20Replacement.pdf

I never actually viewed them as opposite comments, only that the restriction in the heater core feed hose is a design feature intended to direct the bulk of the coolant flow in the engine cooling system, and that the restriction (or lack of) has nothing to do with leaking heater cores.

If one reads this (now horribly hijacked to kingdome come) thread from start to finish, it would be virtually impossible to distinguish fact from fiction, with regards to hoses, nipples, restrictions and such.

My intent was merely a (second) attempt to introduce some more-than-likely-to-be-factual information on the topic, from a respected source.

My own paraphrasing earlier fell somewhat short of the intended goal, I'm afraid.

By opposite I meant is seems in one he's saying restriction doesn't matter and the other he's saying make sure you get the OEM spec restriction nipple.

I like all this talk about nipples :D

Some interesting reading.

http://www.carqueststores.com/common/downloads/partsTechTempcontrolCR331%20Heater%20Core%20Failur es%20and%20Replacement.pdf

There's a few parts I liked...

Under Heater Core Failures:

Erosion of the metal, due to the action of the flow of the coolant through the heater cores. This is usually
present in aluminum heater cores. The faster the coolant flows through the core, the greater the effects of
erosion. The use of an “inlet restrictor” (required on several OEM applications) may be used to slow the speed
of the coolant, as it passes through the heater core.and this one...

Under Other factors to consider when replacing a heater core:

Check the original heater hose for the presence of a coolant flow restrictor. If one is found, care
should be given to install a replacement restrictor in the same place as the OEM.Might be something to this, huh?

While I agree that pressure will be the same with or without a restrictor, flow certainly won't. I continue to stand by my original statement:

$10 for the right part is pretty cheap insurance

Hi guys-I ended up going with the $8.03 replacement part from NAPA. It literally took about 3 minutes to install. Considering the old one lasted 14 years and 176K miles, I think that's a pretty good run.

Or if you live in the south you could just add cutoff valves like mine and kill two birds with one stone. - cut the heat out of the cab in the summer by stopping the circulation and restrict the flow because the gas valves I used have small holes when the valve is open.

I'm still not convinced that the rate of flow has anything at all to do with leaking heater cores....or corrosion.

ROFL - neither am I, but up here in the frozen north, we don't take chances with our heater cores... even a minuscule leak means your windshield fogs up and ices over from the inside.

It's a cheap part, and I'd rather not have somebody say "I told you so" while I drive down the road, busily scraping my windshield on the inside so I could see..:)

BTW - I like your shut-off valves... cool idea!

I figured that restricter was there for some reason........GM engineers, They got it half right.