What did I do?

Stephen Newell · Sep 17, 2018

Not sure yet but I think the thermostat when out on my 93 G20 chev van. It managed to overheat so I pulled off the road and it died. Then I let it sit for over an hour to cool while I had someone bring some water and antifreeze. Then I refilled the coolant and went to drive it home and it blew a very thick white cloud of smoke for the first ten miles and also the engine ran rough. Then before I went the next 15 miles home the smoke quit and the engine started running better with the exception of more valve clatter than it already had. After it sat for a while again I checked the engine oil for water and there wasn't any on the stick but after wiping the stick to get the oil off it didn't have enough oil to read. I just topped off the oil a couple days ago and it hasn't been using oil. In the morning when it cools completely I will start the engine and see what happens. I can understand the thermostat purging the engine of coolant but I don't understand the oil too. Thoughts?

old · Sep 17, 2018

Check all fluids before you so much as touch the keys. Did you by chance mix antifreeze types?? Low on oil could mean a hole in a piston or broken rings on a piston etc. But it sure does not sound good

tomturkey · Sep 17, 2018

My guess-head gasket, that smoke you saw was probably steam. As I said, my guess. gobble

David G · Sep 17, 2018

I would bet on head gasket over thermostat.

Janicholson · Sep 18, 2018

Do not try it out. 5 minutes of operation can wipe the crank and ruin the engine. If a head gasket went out, do a combustion gasses in coolant check from An auto parts store, cheap security. A cooling system pressure check is also advised. Do not start it before these checks. Jim

used red MN · Sep 18, 2018

Some where in about that range of years they had trouble with the intake manifold gaskets deterioration around the coolant passages on the ends of the heads. Usually leaked in to the lifter valley so coolant in the oil was the general issue. Unfortunately this sounds like it is possibly the head gasket.

Stephen Newell · Sep 18, 2018

I think the thermostat is the root of the problem. I think it caused the engine to overheat and damaged something else. My first thought when I saw the smoke was a cracked block and later thought of the head gasket however I don't understand how it could get better by driving it.

Stephen Newell · Sep 18, 2018

How effective would this test be on a high mileage vehicle? It's possible the motor may have 233,000 miles on it.

Geo-TH,In · Sep 18, 2018

X2, my vote is head gasket.

Bruce(OR) · Sep 18, 2018

i hate my computer.
it crashed on me just when i had your problem worked out,
This will be a shorter version. Email is open.
Fill oil first.?
Blown head gasket. Pull plugs, pressure check system. Coolant will come out of bad cylinders. Green tinted spark plugs might also be an indicator.
Stuck? rings possibly causing oil consumption to go up.?
Compression test at least with thumb over hole,? If thumb not forced off hole while cranking, bad hole. Forced off weakly? Weak hole. Add PB Blaster /
Seafoam Deep Creep / Kroil - pick one of the three. Soak overnight. leave plug out, crank engine clearing cylinder. Install plug and start. Will smoke until junk burned out.? Bad head gasket needs either KR Block seal or Blue Devil block seal. Read directions each can is different.?
Change stat. Make sure new stat has 'piddle' valve.??
Questions? Contact me.

M-MAN · Sep 18, 2018

Look for where the oil escaped first. Drain plug, filter, etc. My guess is that's where your problem started. Losing the oil will overheat an engine too.

The white smoke and skipping is bad. With that era Chevy intake gasket would be my first guess. When my bil's went bad it would do that until the coolant level dropped enough. His solution was to loosen the radiator cap and run it a little low. It will get the head gasket if it hasn't already.

Steve@Advance · Sep 18, 2018

I suspect a cracked head, very common with those engines.

It could have gotten low on coolant, or the thermostat failed. For whatever reason it overheated. Then when the coolant was refilled, it began entering a cylinder, which explains the smoke (steam) and rough running. As the coolant depleted the steam stopped, but would have began the overheating again.

As for the oil loss, not sure what happened there.

Doesn't sound good, I would be cautious investing in repairs to the top end with that many miles and the overheating, sudden loss of oil.

John730D · Sep 18, 2018

It could be any number of things, but as stated below I would suspect the intake manifold gaskets first. Very common for that era of Chevys. It would cause the exact symptoms you described.

blue_tractor_man · Sep 18, 2018

My 91 Chevy 5.7 TBI began using water then started blowing steam out if the exhaust pipe. Had 2 cracked heads. I never ran it hot. My mechanic took the heads to the machine shop, and the machinist said "Don't leave those heads" He walked over and pointed at cracks in both heads. He said "Good luck finding two heads". But the mechanic managed to find two rebuilt heads, put them in, and so far, so good.

Stephen Newell · Sep 18, 2018

I will try some of these things before I attempt to email you. While I have a compression tester because of how tight the engine fits in the van there is no way to use it without pulling the engine. I think I may be able to get my fingers in the plug holes and an inspection camera into some of the cylinders.

I also plan to drain a little oil into a jar and see if there is any water in the oil.

The cooling system does pressurize. When it overheated last night I had to wait about an hour before I could let enough pressure off I could remove the radiator cap.

jimg.allentown · Sep 18, 2018

After reading all of the other opinions, I have reached the conclusion that at the mileage you state, it is most likely that you will not get it fixed by any simple means.

First thing is that what you are told about the intake manifold gaskets is true. Seen it many times.

Second thing is that the engine is also prone to cracked heads.

Third thing is that I disagree about the thermostat being the culprit. More likely is that you were losing coolant right along. Finally got low enough to cause overheating. Too late to blame the thermostat. If the thermostat had stuck closed, you would have overheated very soon after starting out. Once underway, thermostat is open and will stay open unless the engine cools off.

With mileage over 200,000, it may be time for a replacement.

Kansasredneck · Sep 18, 2018

Getting major work done on those vans runs a pretty penny. Same thing happened with my 99. Cheaper to buy another used van.

Janicholson · Sep 18, 2018

Both tests work on any age vehicle. Jim

Ozlander · Sep 18, 2018

(quoted from post at 07:36:05 09/18/18) I also plan to drain a little oil into a jar and see if there is any water in the oil.

No need to drain a little oil, just loosen the drain plug and see what drips out. Water will be on the bottom.

Clarence Slydell · Sep 18, 2018

(quoted from post at 10:06:05 09/18/18) I will try some of these things before I attempt to email you. [b:f4109086b1]While I have a compression tester because of how tight the engine fits in the van there is no way to use it without pulling the engine. [/b:f4109086b1]I think I may be able to get my fingers in the plug holes and an inspection camera into some of the cylinders.

I also plan to drain a little oil into a jar and see if there is any water in the oil.

The cooling system does pressurize. When it overheated last night I had to wait about an hour before I could let enough pressure off I could remove the radiator cap.

How would you change the sparkplugs?

Stephen Newell · Sep 18, 2018

I did that and there was no water in the oil.

Stephen Newell · Sep 18, 2018

That's not really an option. I've done thousands of dollars of customizing on the van to fit my needs plus I just paid a guy a lot of money to rebuild the front end. It will have to have a rebuilt motor.

Stephen Newell · Sep 18, 2018

I did take the thermostat out today and it was froze closed. From where I am right now regardless if it's a cracked head or head gasket it will involve removing the motor from the van. If I'm going to do that I will just get a rebuilt motor to replace it. I think I would be better off in the long run. I could change out a motor but I don't have the talent to overhaul one.

Stephen Newell · Sep 18, 2018

I've pretty much thrown in the towel on that motor. I ran it briefly today after changing the thermostat and it really started blowing water. I plan on just replacing the motor.

What did I do?

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