3.8 coolant loss help

[fredfast]

Originally Posted by Jed Rule

Bulletin 01-06-01-007A refers to 3.8 engine vin K for the following models
1995 - 1997 Riviera
1995 - 1998 LeSabre, Park Ave, Bonneville, Eighty Eight
1996 - 1998 Regal
1998 Lumina, Monte Carlo, Intrigue
1997 - 1998 Grand Prix
1995 - 1996 Ninety Eight

The bulletin instructs you to replace BOTH the upper and lower manifolds. The kit from KenCo will save you replacing the lower. It's expensive for 2 little parts but saves you a lot of work. The dealer I got it from did not recommend the Dorman replacement manifold. They said it didn't last like the GM ones. (Once you eliminate the cause of the failure). I saw a Bonneville with only 60,000 that melted right thru to the coolant passage. Engine was locked solid. Had to take out the spark plugs to see if it would turn. The overflow jar was full but the radiator empty

Has G M corrected the intake plenum and TCC and oil consumption problems in the current models? I would be hard pressed to buy another LaSabre.
Thanks,Fred

[nick0750]

they have not corrected the problem, they still have plastic upper intake plenums and they will all leak at some point or another it a poor design on a good motor. thanks engineers..

[95 LeSabre]

My VIN has an L for the 8th digit, does this mean I do not have anything to worry about? Also, if the hot EGR tube is what is causing the problem, couldn't you just remove the EGR system and plug the hole?

[imidazol97]

Originally Posted by fredfast

Has G M corrected the intake plenum and TCC and oil consumption problems in the current models? I would be hard pressed to buy another LaSabre.
Thanks,Fred

That was fixed in 1999. The 2000 and up had a sealing recall around the air intake. They put coolant antileak back in like they used to do at the factory but had quit in 2000 and put on larger bolts to hold the intake and throttle body together.

[joe123999]

Thanks for everyones input. I was glad to find a solution for the coolent leak in the intake for my. I replaced the upper manifold in an afternoon. It is holding after 2-days. I hope I never have to do this again.

Coming from a engineering background I was shocked to see the how the coolent ran from the lower intake manifold to the throttle body (through the PLASTIC upper manifold). This must have been a bandaided last minute solution by the engine manufacturer. My guess is the throttle body iced up and wasn't found till too late. The quickest and cheapest solution was probably to route the coolent through the upper intake manifold. The real solution could have been to short the intake manifold and lengthen the throttle body. The coolent should never have been run to the throttle body this way. The coolent and the EGR exhaust port probably should run through metal-to-metal surfaces only. Another factor that could cause the upper intake and throttle body gaskets to is wear from vibration. My throttle body had a one bracket supporting it to the lower intake or head. Combine the vibration with heat and you know the rest, a hybrid engine that runs on gasoline and Dex-cool.

A posible design fix could have to design the manifold so the coolent doesn't leak into the intake and leak. A couple extra gasket linings would have done this.

Also, the EGR is definitely shouldn't be close to a plastic surface. Maybe this should have been ported directly to the throttle body, therby reducing the need for the coolent to supply the heat.

[HotZ28]

From the original design of the TPI (Tuned port injection) motors built in 1985, GM did a fine job running the coolant through the throttle body (all aluminum) and the EGR was built into the aluminum intake. Therefore, we never had a problem until the invention of plastic intakes. I assume that a co-op Engineering student in training, designed a plastic intake and convinced his boss and Sr. staff that they could increase their bonus potential with a new cost savings idea, and they all jumped on the gravy train. I spent 40 years inside "Corporate America" and know how the system works. Penny pinching is the only way to increase the "bottom line" and get those big bonuses.

Plastic is cheap, and the throttle body still needs heat to keep the throttle plate from freezing in extreme temperatures, therefore the design was implemented without long term testing.

Ford also jumped on the gravy train and used a similar design, however at least they had enough balls to do a recall their cars with leaking intakes!
GM will never have a set like Ford!

[joe123999]

I almost forgot, my car was a 1998 Buick Lasabre custom, V6 3.8L (k) engine, 42000 mi.

I think I blame the wear on the gaskets more from the vibration and not the EGR heat. The gaskets near to (between upper and lower intakes) and on the throttle body were worn smooth (compared to the newly purchased manifold). This was probably due to the upper (plastic) intake manifold supporting the throttle body's weight. No signs of melting plastic around the EGR exhaust outlet, however, this still cannot be considered a good thing. I probably could have gotten away with a new gaskets ($50.00), but replaced the whole intake manifold instead ($150.00). The longest part of the ordeal was removing/re-installing the fuel rails and injectors. The changeover took about 5 hours.

Thanks again for everyone’s help.