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Boggled - Engine Overheating

Immortalis

Full Member
Joined
Jun 9, 2018
Messages
14
Hi all.

I've got a 2005 Avalanche 1500 4wd 5.3l

About 2 weeks ago the truck overheated. All the signs (what little there were) told me it was the water pump,even though I replaced the water pump 6 months ago. I tried some other things though first.

- Hooked up the ODBII scanner - Wasn't connecting
- Tested for leaks - None found
- Checked (MOST) of the hoses for cuts/leaks - None found
- Checked for good coolant flow throughout the system (as best as I could with minimal tools and knowledge) - All looked good
- Replaced thermostat - Made no difference
- Removed thermostat completely - Made no difference

By this time, I wasn't very confident it was the water pump anymore but I was running out of thoughts.
I took the truck to a shop to get them to figure out the problem. They said they pressurized the system and it held pressure and nothing leaked out. They then said they best guess was the water pump was bad.

So... I bought a new water pump. In removing the old one, I found one of the hoses WAS cut. (despite holding pressure and not leaking?!?!). The little 3" hose that connects to the water pump was slit on the under side. So I replaced that, but in doing so, broke the Y connector. So, I replaced the Y connector and since I was at it, replaced the hose from the Y to the surge tank. I then installed the new water pump and re-installed the new thermostat as well. - All of that made no difference.

When I was replacing the water pump,  I remembered that the ODB port was connected to the cigarette lighter fuse (which hadn't been working in quite awhile), so after installing the water pump I replaced the fuse and the port was working again. My scanner came back with 2 codes... I forget what they were but the first one was a bad ECT sensor. I replaced that and it helped a little bit... Instead of overheating in 4 minutes, it now takes about 6 minutes. Replacing the sensor cleared both codes though (whatever the 2nd one was).

I'm running out of ideas here (and money)... and was hoping someone had any thoughts?

Just some more random info that may or may not be of use...
- I have been trying to burp the system after adding coolant (several times a day), even though its a pressurized system and doesn't require burping.
- Anytime I say "coolant" I'm referring to water. I've only been putting water in until I solve this, then I'll go back to Dex-Cool.
- There's no coolant leak, but I do lose coolant when it overheats. The mechanic said it's it's an aluminum rad with plastic end caps which act as a pressure release so when it gets too hot, the pressure (and coolant) are ejected from there.
- My rad has no rad cap and no petcock
- Since all this started... my truck now chokes a bit trying to start up... but aside from the choking, she sill starts fairly easily.
- When it starts, there's a puff off white or greyish smoke that comes out the exhaust.
- Since this started, the truck now rides pretty rough if I exceed 70kmh

Thank you all for reading and for any input yous may have. :)
 
Electric fan or normal?
If electric well make sure they work.

IF normal check fan clutch.

Check if heater core is blocked.
Get flush kit and connect to heater core one side and let the other drain on ground.
run garden hose and see if water comes out clean.
If no water or nasty then your heater core and potentially the radiator as well as block are all crusted up with gunk and needs to be flushed.

Check oil?
Is it foamy or milky? then you leaked water into it and have issue.

Are fins on radiator clean?
How about fins on heat exchangers in front of radiator?

Maybe remove lower rad hose to see what comes out...

Could be head gasket?

 
Electric fan.

They're working. Run normal and kick into high when it gets really hot.

I've picked up some rad flush, I'll be doing that shortly.

No garden hose unfortunately. Water is from a well and don't want to put it in the rad. Using bottled water... which is slow, but works.

Oil is normal. Not milky, not foamy, A touch dirty but not black yet.

Fins have a few bugs but essentially fairly clean and no damage.

Lower rad hose just drains out water.

Head gasket... possibly. I wouldn't know how to tell and the mechanic apparently didn't think it was.

I'll let you know the results of the flush when it's complete.

- Thanks
 
I flushed the heater core (both ways) as best as I could with bottled water.

I then flushed the rad with prestone rad flush stuff. It says to get engine to normal temperature then run it for 10 more mins with the heat on high. I only made it to 6 mins, then it got too hot, the fans kicked into high and coolant started spewing out of the side of the rad. So... rad is flushed as good as I could get it  :/
 
Pull the radiator out, and give it a good clean inside and out with a power washer.
If you don't have one, a trip to the coin car wash would probably work  >:D
I had a Firebird with a weird overheating problem, and I had gone through the water pump, thermostat, rad cap, fan, and all that...and in the end, the problem was a restricted rad. In my case, it was restricted on the OUTSIDE. I couldn't see that well because the condensor was in the way. It was filled up with what looked like sheep's wool. Unfrigginbelievable!  ???
So - after I washed the hell out of that radiator and dropping it back into the car, all the overheating and boiling over problems were gone.
In my experience, quite often the thing that causes the problem, you'd never think that to be it!!

CarMech1969
 
Thanks for the input!

My biggest issue at the moment is it's my only vehicle and I live outside of town. If I pull the rad, I can't get to the car wash. I'll definitely take a look at it though. If there's anything there maybe I can clean it our here somehow.
 
What came out of heater core?

you can use hose to wash radiator with nozzle on end if you remove it.
why you are at it hose off condenser too.

When it gets hot does it actually feel like it is that hot?

IE is your gage accurate?
 
You are correct in not using well water or anything other than distilled water. Minerals in the water will coat the inside of your engine and radiator and make them inefficient.

If you turn on the heater full blast do you get good heat?

Sounds like you have air in the system, coated system which the flush should helped with or something wrong with your radiator as already mentioned.

After installing a "new" set of heads on mine it took a while to get all of the air out of my system but I never had an issue with air in the system either. Just the coolant level kept dropping until all of the air worked out. Also check the "steam" line. This is the small line at the front of your engine that connects to both front heads and to the Throttle body then back to the radiator. If there is a kink or issue with that hose setup your heads can't get rid of the air or steam built up and you will have over heating issues.
 
ygmn,

Don't have access to a hose. Run by a slum lord. I bought a hose but they have the outside tap shut off, which makes no sense since it's well water and doesn't cost anything.

I haven't actually touched it to see if they're hot, but the top and bottom rad hoses get extremely hot.


redheadedrod,

When I turn the heat on, it blows cold until the engine temp reaches normal operating. Then you can feel it change. I wouldn't call it hot air though... more like room temperature on a mildly humid day.

So far, the flush hasn't had any affect. As for the "steam line", that's the first I've heard of it. I'll check it out.  Thanks!
 
Immortalis said:
Don't have access to a hose. Run by a slum lord. I bought a hose but they have the outside tap shut off, which makes no sense since it's well water and doesn't cost anything.

That is your biggest problem there.
Take the truck somewhere with a hose tap. A friend's place, a neighbour...wherever.

So if I understand right, the rad hoses get really hot, but the heater core doesn't?
Sounds like the heater core is for sure plugged up.
And if the lower rad hose is just as hot as the upper rad hose, the radiator is not doing its job, and is likely plugged as well.

Here's an idea:
Drain your coolant at home, and then fill with just plain water....and then drive to a coin car wash.
Now you have access to water, and you could drop the water out of your truck right there without having to worry about where to dump the coolant.
Then you can do whatever you want. Clean your rad and heater core really good in both directions with the high pressure water. I bet a lot of crap will get knocked out of there.
Just be careful when cleaning the radiator cooling fins. You don't want to bend them. You'd make the problem worse!

CarMech1969
 
Wouldn't the pressure washer be too powerful and damaging to use for flushing?

Plus, all sounds great but then I get to the car wash and have to sit there for 2 hours to cool down before I pull the hoses :/ #countrylife
 
flush with garden hose and PRestone flush kit here:
https://www.oreillyauto.com/detail/b/prestone-4666/belts-hoses-16454/antifreeze-flush-kit-test-17481/5c22aa2bdb80/prestone-antifreeze-flush-and-fill-kit/afkit/4666543?pos=0

prestone also makes flush liquid to help loosen up junk if you have any.

I have used before and it works well.
Sometimes you need to flush twice as stuff inblock will take more flushing to loosen up and get out.


 
Again, especially with hard water you do NOT want to use your tap water... It could be the reason why your system is f'ed up in the first place.

If you use the radiator flush with hard water you could end up using up all the chemicals in the flush on the minerals in the water.

High pressure washes certainly can damage some components... However the washes should have a low pressure rinse. This could work too but will take a while since its normally low flow.

Without using a non-contact temp sensor you likely won't be able to tell the different in temps between the top and bottom hoses. Some might be able to, but when the top hose is over 200F and the bottom hose is only 150F they both are still too hot to grab a hold of for long.

Your better off going to a relatives house or friends house that has soft water and flushing out your radiator with a hose. You also need to backflush your heater core with the hose. You will likely get a bunch of crap out. When done doing that you use the radiator flush you may have to do it multiple times as already mentioned but only use distilled water. Once you begin flushing with distilled water don't use tap water again in the system.

If your ONLY choice is to use well water ONLY use it to try and flush out particles. It can still coat the inside of your radiator, just be aware your going to need to flush your radiator again. I have had to flush 2-3 times on my vehicles before I knew how bad tap water was for the cooling system. Currently have about 30 gallons of high purity water sitting in the basement for doing the flush and fill in my vehicles.

Note that if your radiator truely doesn't have a drain on it you may not be able to fully flush out the contaminants and may need to replace the radiator.
 
redheadedrod said:
Again, especially with hard water you do NOT want to use your tap water... It could be the reason why your system is f'ed up in the first place.

In my area, the tap water mineral content is so low that the local Exide battery facility uses straight tap water to flood their cells. Imagine that!  :p
I had an original green top Interstate battery that I bought from a scrapyard for $40....used it for more than 10 years....topped up the cells occasionally with our good old tap water as needed - and never had a problem. Went with the truck when I sold it to an 18 year old kid (1992 Gmc Sierra).
Have used it for cooling systems in all my cars and never ever worried about it. It all depends on where the water comes from!

redheadedrod said:
Note that if your radiator truely doesn't have a drain on it you may not be able to fully flush out the contaminants and may need to replace the radiator.

That being said, if any of the fins are starting to crumble, I wouldn't even think twice. New rads are cheap these days!
Another thing. It only took me one time to learn about drains on plastic header tanks. Don't touch them. More often than not, they break, and now you have no way to close up the rad again. I just yank the lower rad hose and let 'er rip!

CarMech1969
 
Hopefully you dont have a head gasket leak thats small enough to evaporate the water before it really molds with the oil. Does your exhaust feel wet when you put your hand over the exhaust? Maybe its leaking toward outside of the head? Look around the engine heads when you turn on the car,  look for signs, and also once the car warms up. Also check the radiator and look for leaks from around the inside area of the bumper. That happened to me already.  Good luck.
 
Sorry it's been awhile since I've posted... been going nuts.

I did a flush of the entire cooling system (using bottles of water... God was that painful). After that, things were better... but not fixed.

My 20 minute drive to work was taking 40-50 minutes since I'd have to stop 5 times to let the engine cool down. I had to stop going to Timmys in the morning because it was slow driving in town and the over-heating issue was too bad.

After the flush, I could drive all the way into town and in to Timmys and the temperature remained normal. That was great! Once I was leaving timmys, the temperature would rise but I could make it to work. I went days with the truck getting hotter than normal and even very close to over heating... but it never did. In some cases, it would get close to overheating... and then drop back to normal temperatures at random.

So after days of this... I took the truck to a (different) shop again and they did a pressure test. No problems. They did a head gasket test. No problems. They did a vacuum test. No problems. They did a bunch of things and found nothing conclusive.

I then decided that since the flush worked so well, I would try to flush it again. This time, I went to a friends place who has a hose and I first flushed it with CLR to try to get rid of any other crap that might still be in there. Then I flushed it all out with good clean water.

After that, the truck was horrible again. Stopping 5 times to get to work again. Its really perplexing and frustrating.

Last night I went to his place again and we flushed it again with the hose. Each part, 3 times, each way.

After that we went for a drive and it over heated within 4km. We stopped, let it cool down, then headed back. We drove for about 30 seconds and then had to stop and let it cool down again. Then we drove again and... we should have had to stop 2 more times before getting back but... the temperature went up... but didn't overheat... (perplexing inconsistencies) and then just as we got back it overheated.

This is really p*ss*ng me off and the most frustrating part is it;s been 3 weeks, I've replaced a bunch of things, spent so much money on this, taken it to 2 different shops and I still don't even know what/where the problem is.

Do I replace the rad? (not that I can afford to), to then find out it's the heater core? or do I replace the heater core to find out it's the rad? or would I replace both to find out it still didn't solve the problem?

The fact that 2 shops couldn't even figure it out doesn't leave me with much hope at all.  :(  :needhug:
 
Replacing heater core would not help.

Radiator maybe if clogged....

I would replace the thermostat again since you say it happens randomly... it is about the one thing that can fail randomly... then work again...

Also are you sure you are getting the air bubble out?

Maybe gage is OFF how do you know it is HOT?
I would get a Laser temp gun and check hose temps and radiator temps. (cheap on Amazon under $20 plus cool to have)

When you flushed what came out?
what color water?
any chunks or just what?
 
I'm getting the air out... as best as I can and as far as I know. I run it with the cap off and watch the bubbles come out and when the Tstat opens I add more coolant. The last shop I was at used a vacuum to suck the air out and add coolant to ensure there were no air pockets.

I know it's hot because the temp gauge goes up, messages flash across the console, the fans kick into high and when close to overheating, coolant is forced out through the end caps on the rad. Also, the rad hoses are piping hot. Too hot to hold for more than a few seconds.

When I flushed, there was lots f things that turned up. Brown pasty sludge particles (I suspect might be remnants of stop leak), pieces of rust, a few stones and even some dead flies. The trouble is, with the hoses being so short, there's no way of getting JUST the flush stuff in a container. It flushes out running over parts of the engine, frame and anything else before coming out under the truck and into a container. I suspect that's where most of the particles, rust, stones etc... are coming from. Forcing water out the top of the rad or surge tank reveals small white particles in the water. Like dust.

Water color was very clear, aside from what looked like white dust particles.
 
someone used stop LEAK?

ARGGGGGGGg
brown pasty sludge is a PIA..
you need to flush properly use the chemicals from prestone.

HOw did you flush? tie into heater core hoses?

I tied into one side and with engine off juct ran water thru until all the crap came out.
Thn reversed and did the other way....

Problem is if radiator is clogged then you need to take it out and cleaned if it can be...
old days you would take tanks off and soak core in solution... then resolder rad... but since these have plastic tanks I am not sure if the core can be removed and put back together...

I would try running water thru top rad hose and see what comes out bottom and then reverse tao water is fnie for this as yo uhave bigger issues..

Onse those are done then try fluching block by hooking up to 1 of the heater hoses and blowing water thru until it comes out of water pump lower hose connection..

then try other heater hose...

you have junk in there restricting water flow and it is floating around...

so flush and flush again...

then once deon with cold water flushing... put back together and use the prestone chemicals and follow directions... it works as I did this on a blazer years ago...

takes a while to get all the crud out but you can

good luck

yoru radiator is probably gunked up and some small block core passages alone with heater core.


 
I found an industrial strength rad cleaner.

Yesterday I put the stuff in, waited until the truck got to running temp, then let it run for 10 mins. Shut it off, then let it cool, then repeated the steps 2 more times for a really good cleaning. When we drained the cleaner, we thoroughly rinsed everything 3 or 4 times, each way. With rinsing the rad, we'd but water in the lower hose and block it as best we could so the water came out the top... then we'd squeeze the bottom hose over and over again, pumping the water out the top to give the flowing water a little more force. Then we did the same in reverse. We were filtering to catch all the particles that came out and there was a lot of what looked like calcium particles.

Spent most of the day flushing and cooling the engine.

When it was all done, we went for a drive. I drove it into town, in to Timmys, out of Timmys, went to work, went to the hardware store, went to KFC, went to the corner store and back to my friends place. Temperature remained normal the whole trip. Left the truck running in his driveway while I went in for a minute, when I came out, the temperature had risen some. Took it for another quick drive and the temperature dropped to normal again.

It looks like the industrial flush was winning ticket and seems like it could use another one still but for the most part I thing the problem is FINALLY solved!!!  :D
 
Great news, Immortalis!

The former owner must have used well water if you had calcium chunks coming out!  :eek:
Glad to hear the ensuing saga is finally over  (y)

CarMech1969
 
In a situation like that you may find flushing the engine a few more times over the next few months will help dramatically.
I would run it for a couple months, flush again then do that cycle one more time. You may find by that time your back to "normal".
And use the industrial strength flush. Chances are you got MOST of it but still have pockets of the coating creating hotspots. Only way to really get it all out is as I said, flush a couple more times down the road. The heating and cooling cycles may break some of the stuff loose or make it easier to get it off later.

And a perfect example of why you don't use well water...

My guess is your area has heavy limestone and such water will give that calcium type coating over everything.. Its a great insulator... as your finding out.

Just have to be careful that whatever you use doesn't damage the plastic or rubber in the system. (Such as to the heater core.)

 
I never put well water in it. I had mentioned that flushing the system was quite difficult because I have to use bottled water which really has no pressure to it and is a pain in the ass to do using bottles.

No idea where all the calcium came from (if thats in fact what it was) but I assumed the clogging was from using stop leak when I had a leak issue. Just not sure why it took 6 months for it to clog up.

I'll definitely do a few more flushes with that stuff over the next while.


I want to thank everyone for their thoughts and suggestions in assisting me with this problem!! I appreciate it very much!

Cheers to all! :)
 
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