1994 Chevy Suburban overheating

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Hey guys,

I have a friend that has a 94 suburban with 293K miles and he is having issues with it overheating. I know he's lucky to have it last this long but I know that old Betsy has some more miles in her LOL.

He drove it 200 miles north on a trip and it overheated and had oil coming out of the dipstick tube. He had the oil/filter changed and also added coolant. He did make it home the next day. This was about 2 weeks ago.

It is now overheating after he drives about 15 miles and it also leaks an ounce or two of oil overnight.

I will be looking at it Thursday and wanted some ideas on what direction you think I should go. Guys, its not ready for the junk yard yet. Ha ha ha.

Need to get this Chevy to at least 300K... LOL. Thanks
 
Oil escaping from the dipstick tube is a symptom of crankcase pressurization. Most often, it's due to combustion gases entering the crankcase due to worn rings.

Overheating can be due to low coolant level, thermostat stuck closed, clogged radiator, hoses(s) collapsed, failed fan clutch just to name a few.

I just replaced a radiator on my son's Dodge Ram pickup (2001). He'd never changed the coolant and the radiator was plugged up.


\
 
The oil leak could be a main seal or an oil pan gasket.

As for the overheating, have you replaced the thermostat? And he might want to get the head gaskets checked if it's overheated on him more than once.

I'll be rooting for "Betsy." lol
 
We have had a lot of good times with this Suburban and need to keep her alive. LOL. Many great hunting and fishing trips and she always got us there and back...
 
Any coolant in the oil? if it's over heating that fast mechanical issues could be fault here.

my Vortec 5.7 is at 249k running like new,find your issue and no problems making it to 300..
 
Big old Chevy 350... I will be checking the headgasket, coolant and the thermostat... Also will try and locate where the oil leaks are coming from. Thanks.
 
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It's a 350 the motor will go a million miles and its been done before. Best motor god ever laid eyes on.
smile.gif
 
Originally Posted By: chevyboy14
It's a 350 the motor will go a million miles and its been done before. Best motor god ever laid eyes on.
smile.gif


x100...
 
I would look at the condition of the cooling system (clean or lots of crud). A thermostat, cap and PCV would be some cheap items that probably could use changing regardless.

Remember to never never let it run very low or out of gas. The fuel pumps on those fail if you look at them wrong. But as others have said, the engine will last forever.
 
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I would look at the condition of the cooling system (clean or lots of crud). A thermostat, cap and PCV would be some cheap items that probably could use changing regardless.
 
Pressurized crankcase + overheating may be a head gasket. Do you have the tools necessary to run a compression check?

They are good engines and will last a very long time, just like most pushrod V8's.
 
These engines are more prone to blown intake manifold gaskets, than blown head gaskets. It may be that you will only have to tear into it that far. Always check the easiest things first. Thermostat, PCV, rad. cap, etc. before you tear into the engine. The Chevy V8 is the most successful pushrod V8 in history.
 
Hey guys,

Looked at the 94 5.7 Suburban today and I really did not see any signs of a coolant problem. He now says the engine light comes on and it is not overheating. Oh well...

I noticed a lot of oil all over the passenger side of the engine compartment. Had my friend rev the engine up to 3K rpm and i noticed oil spraying out of the dipstick tube... Checked the PCV and it was fine but still installed a new one. Still spraying oil...

What could cause not having any pressure through the PCV? I am assuming that something is plugged up. Also noticed that he had a lot of carbon(black junk) when I looked under the oil fill cap and when I replaced the PCV... Looks like he could use a Kreen motor oil cleaning. He swears that he changes the oil every 3K miles... Looked really dirty for an engine that got regular 3K oci's. Bad rings like someone said?

Is it common for rings to wear at 293K miles?

A mechanic told him that his throttle body could be really plugged up/dirty and could be causing his issue. The mechanic recommended a throttle body cleaning. Could this be true?

Anything else causing this oil problem? Thanks guys...
 
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The throttle bodies themselves on these are easy to check, just pop the air filter housing off and look. The intake manifolds themselves don't get dirty on these trucks.

From everything you've said here, it seems obvious this truck has been neglected in some kind of substantial way. The problems it's having are indicative of such. Vehicles that are maintained don't just "start" spraying oil everywhere and overheating for no good reason. Something has to have happened to precipitate all of this.
 
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