Overheating!!!!

Ros981500 · #1 03-01-2010, 04:02 PM

I have a 98 chevy K1500, 5.0 with 245,000. I have replaced head gaskets twice. Last set had heads looked at by machine shop said ok. using felpro heavy duty gaskets.replaced head bolts,water pump twice,fan clutch,radiator,4 thermistats from acdelco. all hoses.made sure was not vapor locked, system has no air. oh ya replaced radiator cap. thermistat is opening, upper hose is hot bottum hole is look warm. if thermistat is in the truck starts over heating if stat is out truck tuns 110 degrees. also gauges are accurate shot every thing with infered thermistat. if anyone can help please put your input...took truck to dealer and two different shops and they want to do everything i have done..

cramer_77 · #2 03-01-2010, 04:25 PM

only thing i can say is make sure your putting the thermostat in right, but im sure if you have the skills to replace the heads i would hope you know how to install a thermostat.

Ros981500 · #3 03-01-2010, 05:14 PM

Just pulled valve cover found a little water in the oil sittin on top of heads.is this because the head gasket is leaking slightly. only had the truck runnin for 20 mins after all repairs...

Ros981500 · #4 03-01-2010, 08:31 PM

update just retourged heads. now when idleing truck runs at 210. when u drive it it starts overheating.If u run the heater the truck stilol overheats but if you stop and let it idle it eventally goes back to 210 degrees any suggestion?

j cAT · #5 03-01-2010, 08:39 PM

Quote:

Originally Posted by Ros981500

update just retourged heads. now when idleing truck runs at 210. when u drive it it starts overheating.If u run the heater the truck stilol overheats but if you stop and let it idle it eventally goes back to 210 degrees any suggestion?

pressurize the coolant system to 16psi ..then see if it holds pressure...

heads could be bad....

display your torque , and tightening sequence ..

Ros981500 · #6 03-01-2010, 09:18 PM

tightened to 70ft lbs. holds pressure. just overheats while driving not at idle. heads have been machined and rebuilt

j cAT · #7 03-02-2010, 10:06 AM

Quote:

Originally Posted by Ros981500

tightened to 70ft lbs. holds pressure. just overheats while driving not at idle. heads have been machined and rebuilt

the torque of 70 ft LBS is good..did you use the torque sequence pattern...?

your issue is most always a bad head gasket ...as the engine heats up the gasket fails...what could be defective is the block ...what was the condition of the metal surface ?

another thing would be all those head bolt threads in the block , did you chase those threads and clean them ?

with the engine hot see if the pressure holds but remove the spark plugs ..

Ros981500 · #8 03-03-2010, 07:45 PM

Holds pressure with plugs out. used torque sequence and threads where clead. also block is in good shape

rottonrattt · #9 03-03-2010, 08:23 PM

you could try flushing your coolant system to make sure it is geting proper water flow!!

j cAT · #10 03-03-2010, 08:33 PM

Quote:

Originally Posted by Ros981500

Holds pressure with plugs out. used torque sequence and threads where clead. also block is in good shape

sounds good ...next is to ensure you have good flow when the engine is at 210 deg F...with heavy gloves slowly remove the radiator cap when hot and observe the coolant flow in the radiator..then rev engine a few times see how the coolant flows should be very good flow///

if you see lots of bubbles and some oily film this is the exhaust gas getting in there..

also the engine should run at 195deg ..210 is up there ...

are you sure you have the correct thermostat ? what is the manufacturer and part # ?

Ros981500 · #11 03-04-2010, 10:33 PM

THE HEAD GASKETS ARE NOT LEAKING, ALSO THE HEADS ARE FINE AND BY THE WAY THE COOLANT HAS BEEN FLUSHED FOUR TIMES....................AND THE STAT IS A ACDELCO AND IS THE FOURTH ONE.............all thes things u guys have said where in my first post with my problem anyother suggestions. Not try to be meen but I have already tired all this simple stuff trin to diagnose the problem..

j cAT · #12 03-05-2010, 08:36 AM

Quote:

Originally Posted by Ros981500

THE HEAD GASKETS ARE NOT LEAKING, ALSO THE HEADS ARE FINE AND BY THE WAY THE COOLANT HAS BEEN FLUSHED FOUR TIMES....................AND THE STAT IS A ACDELCO AND IS THE FOURTH ONE.............all thes things u guys have said where in my first post with my problem anyother suggestions. Not try to be meen but I have already tired all this simple stuff trin to diagnose the problem..

So how is the coolant flowing inside the radiator,,,, with the cap off..? is there air bubbles ?

what ac stat did you use ?

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