1995 Transport 3800 overheating

mikmic2 · 10-03-2006, 07:59 PM

I probably asked for it, but I just bought a 1995 Transport that has a overheat issue. The guy said he put a new waterpump on it. I can verify this as it looks new to me. He said the shop also put in a new radiator, it sure looks clean and new to me. Anyways, driving about 5 miles down the road, the temperature will start climbing. What did suprise me is he said the shop that did all of the above charged him $600.00 and didn't change the thermostat. I checked the radiator fluid and it looks fine. The oil looks good, not freshly changed though. But anyways I trust all of the information above, as he told me many other minor things wrong with the van, and even offered to let me bring it back to him. He told me all of this before I paid the whopping $300.00. I thought if anything, I have a Olds Silohouette the same year, and parts are parts. But anyways....

When it did start getting up to about 240 degrees, and I was only doing about 45mph, I pulled over. I popped the hood, and noticed the radiator fan was going. I put my hand on the radiator, and noticed it wasn't hardly warm at all. That leads me to believe that the coolant isn't going through the radiator as it should. I checked the radiator hose that leaves the thermostat housing, and goes into the top of the radiator, and it was warm, but not real hot, and the closer you got to the radiator, the cooler it was. Anyways, when I got back into the van, it seemed to be cooled down again. So at an idle, it appears to have enough flow to keep it cool. That made me think Thermostat. Can you believe a shop would replace a water pump, and a radiator, but not the thermostat????

Anyways..... I have heard that the 3800 wasn't prone to head gasket issues, by reading many many posts about this subject before I posted.

Can this really be a simple thermostat change? I've read that a head gasket issue would give similiar symptoms. But in this case, I don't believe it is using any coolant.

I can't get to the thermostat for a week or so, but I don't need this van right now anyways. I just thought someone might have ran across this before with the 3800. I sure have liked my other 3800 in my Olds Silohouette. (Except for the Gas mileage.)

I do have one other unrelated issue. I noticed that overdrive doesn't engage at 55. I can drop it into drive and it is the exact same as it is in overdrive. At 55 I think it was running about 2450 RPM. ( Don't really exactly remember, I just remembered thinking it was pretty high. Over 2300 or so.) I would think with overdrive it should be less. I didn't get a chance to get it up to 65mph. But I know my Silohouette will run a lot less RPMS at 55.

As always, any help on either issue would be greatly appreciated.
Thanks
Mike

LMP · 10-04-2006, 08:34 AM

Indeed the symptoms look like a blown head gasket, which is a rare event for the 3800. BLown head gasket lets air and exhaust invade the cooling system, and the water pump does not pump air....so any remaining coolant will not circulate. Against all odds, it does look like a blown head gasket....Anyway, just removing the thermostat and running without for a while would clear that option. If you had a blown gasket, it would keep overheating anyway.
Codes 21 and 22 prevent shifting to 4th. DO you have the CEL lighted on? ALso, shifting to 4th depends on engine temperature going above 140F...and given what you say about coolant seemingly not circulating, the temp sensor (the one for the computer, not the one for the gauge...indeed there are 2 separate sensors) can be disconnected or something else...however since the fan trigs on, this seems to be correct.

mikmic2 · 10-04-2006, 01:56 PM

Thanks for the reply. I had a couple of questions though.
Wouldn't a head blown head gasket that causes it to over heat, cause you to lose seme coolant?

One other question....

What would be the conditions that you could have a blown head gasket, and not use any coolant?

What is this CEL light you speak of?

LMP · 10-04-2006, 04:13 PM

Obviously, with a blown gasket, you would normally loose some coolant to the engine on the intake stroke...so I totally understand your doubts....and I prefer it to be something else too...

CEL = Check ENgine Light

..mmm..by hte way, other than seeing the needle go up and feeling the radiator cold, are there any other distress signs? Steam coming out of radiator?...IF not....may be you just have the gauge temp sensor gone wild.....which would be , well, ...funny, no? Remove that thermostat and run with free flow...and see what happens.

knuckle ears · 10-04-2006, 06:33 PM

Quote:

Originally Posted by mikmic2

I probably asked for it, but I just bought a 1995 Transport that has a overheat issue. The guy said he put a new waterpump on it. I can verify this as it looks new to me. He said the shop also put in a new radiator, it sure looks clean and new to me. Anyways, driving about 5 miles down the road, the temperature will start climbing. What did suprise me is he said the shop that did all of the above charged him $600.00 and didn't change the thermostat. I checked the radiator fluid and it looks fine. The oil looks good, not freshly changed though. But anyways I trust all of the information above, as he told me many other minor things wrong with the van, and even offered to let me bring it back to him. He told me all of this before I paid the whopping $300.00. I thought if anything, I have a Olds Silohouette the same year, and parts are parts. But anyways....

When it did start getting up to about 240 degrees, and I was only doing about 45mph, I pulled over. I popped the hood, and noticed the radiator fan was going. I put my hand on the radiator, and noticed it wasn't hardly warm at all. That leads me to believe that the coolant isn't going through the radiator as it should. I checked the radiator hose that leaves the thermostat housing, and goes into the top of the radiator, and it was warm, but not real hot, and the closer you got to the radiator, the cooler it was. Anyways, when I got back into the van, it seemed to be cooled down again. So at an idle, it appears to have enough flow to keep it cool. That made me think Thermostat. Can you believe a shop would replace a water pump, and a radiator, but not the thermostat????

Anyways..... I have heard that the 3800 wasn't prone to head gasket issues, by reading many many posts about this subject before I posted.

Can this really be a simple thermostat change? I've read that a head gasket issue would give similiar symptoms. But in this case, I don't believe it is using any coolant.

I can't get to the thermostat for a week or so, but I don't need this van right now anyways. I just thought someone might have ran across this before with the 3800. I sure have liked my other 3800 in my Olds Silohouette. (Except for the Gas mileage.)

I do have one other unrelated issue. I noticed that overdrive doesn't engage at 55. I can drop it into drive and it is the exact same as it is in overdrive. At 55 I think it was running about 2450 RPM. ( Don't really exactly remember, I just remembered thinking it was pretty high. Over 2300 or so.) I would think with overdrive it should be less. I didn't get a chance to get it up to 65mph. But I know my Silohouette will run a lot less RPMS at 55.

As always, any help on either issue would be greatly appreciated.
Thanks
Mike

I have heard these engines can become air locked. Meaning the engine has air in it in some cavities. This usually occurs when work has been done on the coolant side. The water pump is incabable of disloging the air and results in over heating.
Not sure how to get rid of it but I am sure some one in this forum may have an idea.

mikmic2 · 10-05-2006, 02:51 PM

Quote:

Originally Posted by LMP

Obviously, with a blown gasket, you would normally loose some coolant to the engine on the intake stroke...so I totally understand your doubts....and I prefer it to be something else too...

CEL = Check ENgine Light

..mmm..by hte way, other than seeing the needle go up and feeling the radiator cold, are there any other distress signs? Steam coming out of radiator?...IF not....may be you just have the gauge temp sensor gone wild.....which would be , well, ...funny, no? Remove that thermostat and run with free flow...and see what happens.

No other distress signs, outside of the fact that the needle starts out cold and slowly rises until warm up, but it will only get hot when you go down the road, so I suspect the gauge is working normally.

If it was the gauge, I would be happy to laugh. How does one test the gauge. My fancy rayovac temp sensor that I use to use for my nitro R/C cars died on me. I wish I still had that. I will remove that thermostat in a few days here, and as always, will follow up and repost the results.

As far as this airlock thingy. That sounds very interesting. Anybody have any further enlightenment on that subject???

LMP · 10-05-2006, 04:05 PM

In fact there is a screw on top of the thermostat housing to vent the cooling system just to let the air escape after the system has been opened and refilled. If you open that and liquid pours out, consider there is no air lock...

mikmic2 · 10-07-2006, 04:52 PM

Thanks LMP, and knuckle ears. I had a minor surgery, and hope to get to this thing early this week. I will check into that bleed screw on top of the thermostat housing, and if no air comes out, I am going to change the thermostat right away. Either way, I will come back to give the conclusion to what I find. Thanks to everybody, Knuckle ears, and LMP.

mikmic2 · 11-14-2006, 05:42 PM

Well, it turns out there wasn't a new radiator in the van like I initially thought. Between taking the radiator out and having the shop back blast it, and clean it inside and out, and replacing the thermostat, the overheating problem is gone. I came to the conclusion that the radiator wasn't letting hardly any coolant through it, after I took it out, so that's why I took it to the radiator shop. The thermostat change was just for good measure.

Just thought I would reply in case anybody else comes up with a head scratcher like this.

mikmic2 · 11-14-2006, 05:44 PM

And yes I did make sure I bled any air out through that tiny screw on top of the thermostat housing. You should make sure it it has at least opened up the thermostat once and then do it bleed it again. Thanks again for all the help and suggestions.

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