1998 GMC sierra 1500 Overheating etc..

G

gmcsierraguy

New member
Joined
Feb 26, 2014
Messages
10
Reaction score
0
Points
0
Changed hoses, water pump, thermostat, and got a new radiator and still over heating. No coolant in the oil and put a pressure test on the radiator and held 15lbs. Anyone ever deal w/a problem like this? Frustrating that for sure. Don't know what else to do. Any assistance would be appreciated.
 
is it possible for the thermostat to be installed upside down? maybe you got a defective thermostat?? easy to check in a pot of water on the stove.
 
Yes already thought I might have gotten a bad thermostat so I bought another with the same results. But thanks for your input.
 
run the engine with the radiator cap off, run it for a while and look to see if there are air bubbles
if you do you have a blown head gasket or cracked head
vortec heads have a history of cracking
 
98trk wouldn't the pressure test show that I have a blown head gasket or cracked head? Just curious. Thanks for your input. I really appreciate it.
 
engine static compression pressure is eight times more than the 15lbs
and when the engine is running the pressure is way out there
that would be able to push past the smallest of an opening
 
Okay will try running the engine w/the cap off and see what happens. Will let you know what happen. Thanks again.
 
Went to open the radiator cap and poured in dex cool and just kept bubbling without even starting. I couldn't start it due to not enough coolant in the radiator. NOTE: That earlier today I did fill it up and only drove 2 miles and came home. will get more coolant today and try it starting it with the cap off.
 
Poured dex cool in the radiator today and no bubbles. I checked for coolant in the oil and nothing. My thermostat is not set in upside down.
 
don't pour dex cool in you have a problem don't pour money that willk go to waste use water until we find the problem
 
if there is a compression leak it is pressurizing the coolant system which would push coolant to the recovery tank
is it full?
 
your list of what you have done, New radiator cap isn't there
if you haven't, replace it with a Good quality replacement
 
No coolant is going back to the reservoir. In fact im losing it somewhere. Will try and locate the leak tomorrow. Appreciate all your comments thanks. If you can think of anything else let me know. Also I will try a new cap.
 
5.7 vortec also has a history of the intake manifold gasket going bad my did coolant would leak and puddle on the manifold thru the center left bolt
if you see no puddles, it could be leaking into one of the ports
if it is the spark plug squeaky clean, that would require you removing the plugs to inspect them
my truck was a '98 5.7 sierra 1500 2wd 4sp automatic and my intake gasket went bad at 60,000 miles
 
Yes I have the 5.7 to. Will check the plugs tomorrow and change the cap. Keep you informed. Thanks again!
 
Okay today I rechecked the dipstick and see its mixed oil and coolant. Also checked the oil cap and it has a milky white caked up gunk on it. Not good at all. Thanks for all your suggestions and ideas. I know the gasket is probably cheap but the labor will not be for this job. Do you think I should try the head gasket repair/block sealer?
 
My opinion is that, even if you find a sealant that temporarily stops the leak, the problem will return and leave you stranded at a very inconvenient time and place. Also note that if you have a blown head gasket and keep running the engine, you can actually erode a small channel in your block that will be hard to plug or repair. You also may find that your head gaskets are badly eaten away around cooling holes , which will lead to further cooling problems. My '89 1500 truck with the 5.7 engine is now a lawn ornament because of extensive damage following a blown head gasket.
 
gmcsierraguy said:
Okay today I rechecked the dipstick and see its mixed oil and coolant. Also checked the oil cap and it has a milky white caked up gunk on it. Not good at all. Thanks for all your suggestions and ideas. I know the gasket is probably cheap but the labor will not be for this job. Do you think I should try the head gasket repair/block sealer?
Click to expand...

no way would I use a "snake oil" repair on anything.
just got my 4.3 back from the shop for the repair of a leaking intake gasket. cost me $883.... $462 labor... $390 parts, plus tax. that price also included new serpentine belt, idler pulley, tensioner, thermostat housing, an oil flush and 2 oil changes. with 142k miles, there was no way I'd put the original tensioner and idler pulley back on. I think money well spent.
good luck with yours. there are several youtube videos that explain how to do this repair. I'm just a little too old and out of shape to turn wrenches any more.
 
You must log in or register to reply here.

Share this page



Back
Top