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95 LeSabre Coolant Collecting Around A Bolt

06-26-2012, 09:17 AM
I noticed some coolant accumulates around this bolt. It is not coming from the thermostat housing. It seems to be coming up from the bolt:



I dry it with a wad of paper towel, but once the car runs for a while again more coolant accumulates.

What could this be indicative of?

06-26-2012, 09:23 AM
Most likley leaking from the upper intake manifold(plenum). Recomend replacing the entire plenum as they warp and corrode.

06-26-2012, 10:08 AM
And while you've got the top off, change the LIM gaskets to the new aluminum framed ones.

07-04-2012, 06:41 PM
I agree with Tech...

If the lower gaskets have not been done I would replace them... But just to note, there are no aluminum gaskets for the Series I 3800.. The only gaskets are the Nylon gaskets... For that I would recommend Fel Pro..

07-06-2012, 03:23 AM
I agree with Tech...

If the lower gaskets have not been done I would replace them... But just to note, there are no aluminum gaskets for the Series I 3800.. The only gaskets are the Nylon gaskets... For that I would recommend Fel Pro..

Was that a series I 3800? I thought all series I's had aluminum intakes.

07-06-2012, 11:55 AM
All 1995 LeSabre had the Series I L27, which had an aluminum LIM & plastic UIM. Very seldom does either part of the intake require replacement. However, the gaskets do fail after years of use.

07-11-2012, 07:50 PM
The upper intake on the upper intake on the 93-95 L27 will easily do 15 years or so with no issues, But when you remove the upper intake the coolant passages for the TB need to be checked, the passages do degrade to the point that the upper will need to be replaced... Not common but they do suffer the effects of time and heat..

I'd say that leak is either the upper intake gaskets and or the upper intake as well..

Let us know what you find when you get there..

09-16-2012, 03:22 PM
Thanks for all the info gents.

The coolant loss is increasing. I see where it is seeping out: Between the upper intake and lower intake on the right side sort of directly behind the thermostat housing.

Never having done this, is this a very difficult job? It looks to me like a matter of pulling some bolts, remove old gasket, clean surfaces, put back together. Will I just need the upper intake gasket, possible upper intake, throttle body gasket, and lower intake gasket? Should I smear the gaskets and/or mating surfaces with Permatex RTV gasket maker or is that not necessary?

Sorry for all the Qs. Thank you.

09-17-2012, 08:59 AM
Do not use sealant! It's not a difficult job, but does require some patience. Be careful not to damage the injector seals when removing and installing the fuel rail.

Blue Bowtie
09-17-2012, 07:28 PM
GM T1 is correct about not applying sealant to the gasket or flange surfaces, but it is advisable to clean all the LIM bolt threads and apply anaerobic sealant to them on assembly. These work well:


09-23-2012, 01:26 PM
Thank you very much for the direction.

Can someone pls advise what to torque the upper intake bolts to? tks

12-10-2012, 03:00 PM

Well after going through a couple gallons of coolant the last couple of months, I finally got motivated and solved the coolant leak problem.

I took off the upper intake manifold, and couldn't tell where coolant may have been leaking. The gaskets "seemed" ok. Additionally, the coolant passages on the plastic intake were intact and not deformed, that is until I took a screw driver to the wall of one of the passages and it leterally crumbled. At that point there was no question that the UIM had to be replaced.

So I purchased a new Dorman UIM (#615-719). There were 2 challenges with installation. The first was because I didn't understand how to remove the EGR pipe from the manifold, and upon reassembly, I had a problem that sent me to 2 hardware stores before realizing I didn't need the parts I purchased afterall. The second challenge was as follows: On the new UIM, one of the lower bolts that the throttle body attaches to wasn't quite long enough to secure it to the bracket coming off the LIM. Actually there was perhaps only 1 or 2 threads exposed. I had to use a nut from my spare parts bin that just barely caught the exposed threads. Otherwise, the throttle body would have mostly been supported by the UIM (not good IMHO). This is definitely a design flaw with the Dorman UIM, so beware of this caveat, and be prepared for a work-around.

Prior to assembly I used carb cleaner to clean up the LIM, throttle body mating surfaces, and the inside of the throttle body which were all caked with "varnish" or whatever. Using the carb cleaner made this a breeze (strong solvent). If you do this, just don't get carb cleaner on anything plastic or rubber. I also used a Q tip to scrub the underside of the fuel injectors with carb cleaner as there was some varnish there too.

Another thing I did was I cleaned all the bolts and applied plumbers pipe sealant to the threads.

I wasn't clear on how much to torque the bolts, but a couple of vague sources seemed to indicate that 9-10 ft lbs would be appropriate so that I what I did.

I was glad to get it all back together, crank it up, and find out that the leak had been fixed. Thanks for all of the advice, gentlemen. Once again I would have been lost without the pointers.

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