Strange coolant leak

GBertolet

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I have a 1998 LeSabre with the 3.8 engine. I was driving it today, and I experienced missing, bucking, stalling, and erratic shifting, similar to overheated engine behavior. Luckily I was on back roads, and a mile from home. When I got home, I discovered antifreeze under the left front of the car. When the car cooled down I checked the radiator, and it was empty. The check engine light was on solid, and the ABS light was on for a few seconds, then cleared. My code reader said, P0100 multiple misfires. The suggested cause was MAF. I removed it and cleaned it, discovering the air box had coolant in it, along with the corrugated hose leading to the MAF. I guess that's why the MAF fault. Is it possible coolant can come out of the intake, into the air filter, against the intake air flow? I fear a head gasket failed. I had a head gasket replaced 3 years ago. Any diagnosis would be appreciated.
 

HotZ28

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It sound like the UIM has failed due the the EGR tube burning through the plastic where the coolant circulates behind the throttle-body. Was the UIM replaced when the head gasket was replaced?
 

RobR

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The answer simply,is yes. Time to replace the intake plenum. While your at it do the lower intake manifold gaskets as well,as the plenum needs to be removed to get to them,and they are plastic and prone to leaking. I recommend the ATP Greyworks plenum,as it is redesigned to lessen the chance of leaking,and the new design ACDelco LIM gaskets which are metal. The total labor is 3.8 hrs,so don't let anyone double dip on the labor. IE charge you additionally remove the Plenum,as that is included in LIM labor hrs. Very common problems and there is a ton of info on the web about it.
 

GBertolet

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Is this a job I can do myself? I would need a step by step tutorial or detailed documentation. Not afraid to tackle tough jobs, I just don't want to have something apart, and not know how it goes back together, what all parts I am going to need, or any special procedures needed for the repair or reassembly. I will look for my receipt for the head gasket replacement, and see what all was done.
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GBertolet

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I found the bill for the head gasket job. I think the manifold was replaced.
 

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Alan 55

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I found the bill for the head gasket job. I think the manifold was replaced.

I read the invoice and it seems the upper intake was replaced. I recognized the part number as the Dorman unit which has served me well on at least three 3800 engines. By looking at all the parts that were replaced, in theory, you should be in good shape. However the symptoms that you describe seem like a bad upper intake or lower intake gasket. This is a mystery but a tear down may be necessary to solve this. When you pull your oil filler cap, do you have a milky substance on the inside of the cap?
 

RobR

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LIM gaskets and leaky plenum due to heat damage from the EGR chimney are most common causes of internal coolant leaks in a Series II 3800. Thats where id look.
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GBertolet

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No milky residue at the oil cap. My oil level does seem to be higher though. I have synthetic oil, and the oil on the dipstick does not look contaminated, but who knows, maybe it is. I think after the repair, an oil change would be in order.

I just watched on utube a video on a upper manifold change on a 3.8 engine, on a 1995 Olds. The poster's gasket failed at the EGR tube. Actually it melted. Even though the manifold looked OK, he replaced it anyway. The job didn't look too difficult. Just disconnecting lots of stuff, and remembering where it went. I guess that's why they invented digital cameras. I will start the teardown soon, and see what I need, and will report my findings.
 
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GBertolet

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They say a picture is worth a thousand words. So here is one. Do all gaskets needed come with the manifold?
 

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RobR

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They come with all the gaskets. Get the ATP plenum because its the only one with a metal sleeve in that area to minimize heat damage and also a reduced diameter egr chimney to reduce heat transfer. If your goin all the way to the LIM gaskets,which is a good idea,get the metal ones.
 
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imidazol97

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I agree with the ATP plenum. I bought it from a supplier online IIRC. It has the metal sleeve in the vertical tube
that takes exhaust gases up and into the incoming air stream. The hot EGR gases through the plastic ABS original styles heats that plastic and it crystallized on my second upper intake, letting coolant go through the wall into the air stream. The coolant is going through internal tubes to warm the throttle body end of the upper intake--the hot coolant actually goes into the metal throttle body to warm the incoming air to help control the combustion parameters.

If you have several tools and patience you can do this job. I took two days back in the 2000s to do my 1998 leSabre for it's second replacement. Dealer did the first.

I looked at the billing you provided and I can't imagine why the mechanic needed to replace the belt tensioner, other than the coolant goes through it and they didn't want to clean the o-ring areas to make the replacement o-rings seal properly...

They replaced so many things that I would not have replaced for a head job.

Get the metal reinforced intake manifold gaskets where the metal intake sits against the top of the heads.
Get the Dorman metal heater elbows that join up with the belt tensioner.

Label things with pieces of masking tape. I used many different containers for different screws and bolts.
These days people often take pictures of various pieces as they remove the bolts so they know where they go back.

View several different videos on youtube which I am sure now exist for cars of your era that have the 3800 and how to do the upper intake.

I do suggest new spark plugs and two oil changes. Put in cheap oil for the restart and run it a couple hundred miles to pick up residual coolant in the oiled area. Then change it to the good stuff.
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GBertolet

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Thanks, guys, I ordered the suggested manifold from Rock Auto, last evening. It was around $80 with tax and shipping. ETA Friday by Fed Ex. I will finish tearing the engine down, by Friday. I am taking plenty of pictures, in case I get confused on reassembly. I do agree on the two oil changes. Who knows, how much coolant went in the oil, and just draining it once, is unlikely to get it all out.

I did have the metal heater elbows installed, as part of the repair job.
 

GBertolet

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The new manifold came today. I finished tearing the motor down. Coolant everywhere inside the old manifold, some down into the cylinder ports. I used a suction tool to remove the coolant from the cylinder ports, and used an airgun to blow out the remaining coolant out of the ports, what ever I could. One cylinder was totally full of coolant. The others were not so bad. The engine could not of possibly ran with this much coolant flooding things out. Most of it must have leaked out when I removed the manifold. I did drain the cooling system beforehand, but it didn't seem to help any. Is this common on this job? I did get a bag of small parts with thee manifold, and I will have to decipher what they are all for.
 

RobR

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Your lucky you didnt hydrolock. Yes,common. Ya got some fuel injector gaskets and smaller diameter replacement chimneys in the bag.The pcv valve gets swapped over from the old plenum.
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2007LucerneCXL

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You may want to pull all the plugs and crank the engine to get any additional coolant out of the cylinders as mentioned in the above post about hydrolock, blowing through the intake side with plugs out and piston up wouldn't hurt either.
 

HotZ28

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The new manifold came today. I finished tearing the motor down. Coolant everywhere inside the old manifold, some down into the cylinder ports. I used a suction tool to remove the coolant from the cylinder ports, and used an airgun to blow out the remaining coolant out of the ports, what ever I could. One cylinder was totally full of coolant. The others were not so bad. The engine could not of possibly ran with this much coolant flooding things out. Most of it must have leaked out when I removed the manifold. I did drain the cooling system beforehand, but it didn't seem to help any. Is this common on this job? I did get a bag of small parts with thee manifold, and I will have to decipher what they are all for.
That coolant in the plenum & ports is common due to the UIM failure. (See pic below)
After the UIM replacement you will also need new spark plugs! Remove all the plugs and turn the engine over to blow out the remaining coolant in the cylinders before installing new plugs. As mentioned, don't forget to change the oil & filter two times! Follow the UIM install & torque instructions as shown in post #13 and you should be good to go. ;)

068.jpg
 

HotZ28

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I noticed in the pics shown in post #10 that the EGR stove pipe appears to be the original size, not the reduced size. IIRC, the Dorman solution was to beef up the plastic around the stove pipe, not supply the reduced size. The original UIM had three date of manufacture stamps on top of the manifold that looked like three clocks. They indicated the day, month & year of manufacture. Just to be sure that the UIM was replaced, look for those stamps. If none are present, that means the UIM is an aftermarket. If you want to post a pic of the top we can tell you if it was replaced. Looking at the invoice, I see no mention of valve cover gasket replacement? If that was not done, it would be a good time to do that while the UIM/LIM is removed!
 

GBertolet

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I was watching a replacement video for the manifold, and the person doing the work used red loctite and staked the new EGR pipe in place. I don't think it was an ATP manifold. Is this step necessiary, as I don't see it in the ATP instructions?

I took some photo's of the old manifold. Is it the original OEM, if so, did I get ripped off?
 

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