Question about the dreaded intake problems.....

Is the 3800 series II engine affected by the intake gasket problem too? I read somewhere that the EGR valve makes the plastic on the upper intake brittle and can cause it to crack, but I couldn't seem to find anyone about the gaskets failing.

What year is your car? I think by 2004 GM had addressed the issues of the junk gaskets. If your car is older than an 04 I would think that you could have the problems with the gaskets.

As far as the EGR burning through the upper intake, the only way to really fix that is to get an aftermarket intake that is aluminum and not plastic.

Let us know how things go for you.

Intake gaskets are rarely an issue here, as you said the UIM is the culprit.

My '04 Impala was manufactured 6/2004 so hopefully if it was ever an issue, it was fixed before mine. I already had an Alero with the 3400 that had a leaky intake, but luckily it leaked out instead of in and happened when I had 2,000 miles left on the warranty. The Impala is GM certified so I have 3 months/3,000 miles of bumper to bumper warranty left.

The reason I asked was because I heard a whooshing sound under the dash when I revved the engine or took off from a stop. It turned out that the coolant reservoir was empty and the radiator was a little low on coolant so I could hear it whooshing through the heater core. The car only has 22,000 miles on it, so I have no idea what happened to the coolant. Any ideas?

Better get it checked out, have it pressure tested to see if it hold pressure for starters.

For clarification, GM made a revision in the UIM in mid-99 to address the EGR stovepipe issue that was the problem on the early 99-back VIN-K 3800, but continued to use the same POS gaskets, which are the issue on mid 99-05 VIN-K 3800's. It's the same gasket used in the early models, but they lasted longer than the 1st design UIM. If the bad gasket is let go too long in the redesigned UIM, it will erode around the cooling ports (instead of the EGR pipe) and cause the same symptoms.

Probably best to get it back for service before the warranty expires just to be safe. :grinyes:

Maybe the level wasn't checked properly by the previous owner(s) or during the multi-step GM certification process. Low coolant level will cause the gurgling sound you hear in the heater core. Also, you will get some evaporation of the the coolant in the reservoir. Although not as common as the LIM gaskets in a 3400 engine the LIM gaskets can cause an un-explained loss of coolant and are a known issue on the SII 3800 engine. GM came out with the revised aluminum framed LIM gaskets after your Impala was produced. Also, look for any visible coolant leaks (external) at the LIM and UIM areas to include throttle body, thermostat housing, 90 degree plastic elbow (heater bypass), tensioner assembly, and heater hoses.

Another common cause of the gurgling sound is a flaky thermostat especially if it is the original Delco one. It is either opening too soon or not closing completely once the engine is cooled down or cold. Also, it may cause erroneous coolant level indications. You can remove the thermostat and see if there is an air gap indicating it is not closing fully. It will still look like the engine warmup is correct and not set off any cooling system DTCs like P0128 or cause overheating. Best thermostats to use are either the 195 degree AC Delco Premium series or the Stant Superstat brand with a new rubber seal.

I have an '01 Impala LS, 3800 series engine... My UIM gasket was replaced about 6 months ago... But I am now starting to see some unexplained coolant loss... About every 6 weeks the low coolant light comes on and when I open the radiator cap the level is about 1 inch below the top... So I top it off with 50/50 premixed Dexcool and the light goes off for another 4 to 6 weeks... I'm suspecting the LIM gasket now... What do you think??

I have an '01 Impala LS, 3800 series engine... My UIM gasket was replaced about 6 months ago... But I am now starting to see some unexplained coolant loss... About every 6 weeks the low coolant light comes on and when I open the radiator cap the level is about 1 inch below the top... So I top it off with 50/50 premixed Dexcool and the light goes off for another 4 to 6 weeks... I'm suspecting the LIM gasket now... What do you think??

It is possible Bob. As maxwedge pointed out you might want to get it pressure tested. Why was the UIM gasket replaced? Were you losing coolant before that?

It is possible Bob. As maxwedge pointed out you might want to get it pressure tested. Why was the UIM gasket replaced? Were you losing coolant before that?

I had brought the car in when the fuel pump died on me (you remember that saga?!)... While the car was in the shop I mentioned about the slow coolant lose and they replaced the UIM gasket... Both the fuel pump and the gasket were covered by the GM Major Guard warranty...

I had brought the car in when the fuel pump died on me (you remember that saga?!)... While the car was in the shop I mentioned about the slow coolant lose and they replaced the UIM gasket... Both the fuel pump and the gasket were covered by the GM Major Guard warranty...

Oh yeah I remember that Bob. :rolleyes: Do you still have any warranty coverage left? Unless you do the work DIY replacing the LIM gaskets will be costly to include diagnostics. Out of curiosity how much coolant are you losing now?