Still not cooling!

[80jay]

Well my truck is still overheating when I have the ac running at a stop light, so far i flushed the rad,changed the cap,replaced rad hoses,new clutch fan, and new thermostat. Only thing left is water pump and rad, anybody think those could be the problem?

I drove it to work today noticed the gauge started to spike, then I smell coolant so I opened the hood i squeezed the upper hose it was very solid, and the lower hose was leaking. I also noticed that when i got home i pulled the cap off to relive the pressure and coolant was not low, so i put the cap back on and started it up and waited a while and the hose never got solid agian it was soft. Is it by chance the thermostat could be defective?

 

[Gieser]

Only thing left is water pump and rad, anybody think those could be the problem?

There is a way to test the water pump to see if it is going bad or is bad that I saw on another thread here. Let me search and see if I can find it.

Is it by chance the thermostat could be defective?

Is the thermostat OEM? I went through 3 that were not ver good or defective and decided to get OEM and never had a problem after that.

 

[80jay]

The thermostat is aftermarket unfortunately.

 

[Gieser]

The thermostat is aftermarket unfortunately.

I believe you can get one new here for $17.52 or I am sure from CDan and that is where I would start if it seems to be fine for a while one moment and not so fine another. Could be getting stuck IMO.

 

[bigbrowndog]

You can pull the thermostat out and put it in an old saucepan containing water and heat it on the stove to see when it opens if you have a theremometer you can then check the opening temperature against its rating.
I had slight problems with cooling after fitting my turbo and everyone was saying"ya overfueling" as I had no problems before hand. Every year I have drained and reverse flushed my radiator also in the tropics we do not get temperature variations like you guys. But after being told that probably 10 to 20% of the radiator would most likely be blocked I changed it for a new one. Much better and I was able to wind my fuel pump up higher again. have you drained and reverse flushed the radiator? Also when I drained the block at the block drain bolt there was rust around there although I run glycol coolant always.If the engine has overheated the glycol seems to become slippery and does not work as designed.It may pay to pull the pump out and inspect the impellor for wear also before this check the pump bearing for wear , can you move the pump shaft with the belt off?

 

[80jay]

What the downside of running with out the theromstat for a little while to see if thats the problem? I have not back flushed the radiator, and the pump bearing seems to be good still it dosen't have any slop when I move it back and forth.

 

[bigbrowndog]

What the downside of running with out the theromstat for a little while to see if thats the problem? I have not back flushed the radiator, and the pump bearing seems to be good still it dosen't have any slop when I move it back and forth.

This can cause the water pump to cavitate and not pump correctly and also the motor can run below the desined temperature. Short term would be ok I guess though I am not familiar what motor you have. The ends of the impellor vanes wear on some pumps but again I am not familiar with yours. You should do the radiator every start of summer as in your colder winter there would not be that much circulation going on and block scale etc settles in the bottom pipes of the radiator.You guys seem to be getting a rush on overheating and air con problems now that summer's arrived, still 26/27deg celcius here, winter, LOL. what's that.cheers

 

[cary]

What the downside of running with out the theromstat for a little while to see if thats the problem? I have not back flushed the radiator, and the pump bearing seems to be good still it dosen't have any slop when I move it back and forth.

The truck may not cool properly without the thermostat. The thermostat also acts as a flow restrictor and keeps the flow of coolant at an optimal level. If you have to much flow, the cooling system cannot function properly and may still overheat. In the old days when you removed a thermostat from a drag car, you would still put a flow restrictor in to make sure the cooling system cooled as well as possible.

 

[80jay]

the only reason i wanted to take it out of the picture was to figure out if that was the cause of my truck overheating, if so i would just go oem this time

 

[bigbrowndog]

the only reason i wanted to take it out of the picture was to figure out if that was the cause of my truck overheating, if so i would just go oem this time

Yes I would try that short term myself also try the stove hot water it works also.
I should have mentioned to run the heater/heaters as you fill the cooling system even measure the amount of coolant or water you put in to make sure you do not have an air lock in the head or block or heater lines. cheers.

 

[80jay]

thank you.. I will definetly try those things see what happens.

 

[MLX450]

radiator might be clogged. Replace or have a pro clean it out.

 

[80jay]

when i start moving in traffic agian all goes back down to normal temp even with the ac on.

 

[Taz]

After changing every possible part with no major effect, I installed an electric 1600 cfm 12" pusher fan in front of the condensor that solved my overheating problems at slow speeds and dle.

 

[80jay]

Taz what brand is it? I was loking into that, im trying to find the slimest one that will fit in there.

 

[CreeperSleeper]

After changing every possible part with no major effect, I installed an electric 1600 cfm 12" pusher fan in front of the condensor that solved my overheating problems at slow speeds and dle.

I've been thinking of doing that too. Or replacing the mech fan with elec. Has anybody done that?

 

[e9999]

The truck may not cool properly without the thermostat. The thermostat also acts as a flow restrictor and keeps the flow of coolant at an optimal level. If you have to much flow, the cooling system cannot function properly and may still overheat. In the old days when you removed a thermostat from a drag car, you would still put a flow restrictor in to make sure the cooling system cooled as well as possible.

that's odd. How could removing an obstruction -therefore increasing flow rate and/or local pressure- result in decreased cooling?

 

[cruiserman]

when i start moving in traffic agian all goes back down to normal temp even with the ac on.

Check your fan clutch.

 

[Darwood]

that's odd. How could removing an obstruction -therefore increasing flow rate and/or local pressure- result in decreased cooling?

Easy, the fluid circulates too fast through the radiator and isn't given enough time to loose it's heat via said radiator.

 

[e9999]

Easy, the fluid circulates too fast through the radiator and isn't given enough time to loose it's heat via said radiator.

nope