Replacing Intake Manifold Gaskets...Upper Plenum Options?

[Chromium]

My 2003 Buick LeSabre is leaking coolant where the throttle body attaches to the upper plenum, so I'm planning to replace the plenum and upper intake manifold gaskets. I assume it would be advisable to replace the lower intake manifold gaskets and valve cover gaskets while everything is apart.

The only problem is, I can't see to find a replacement plastic plenum that has decent reviews. All the aftermarket ones, including Dorman, seem to have a lot of negative reviews lately concerning quality control, uneven gasket mating surfaces, gasket fitment issues, etc. Has anyone had luck with a particular brand for this repair? The options appear to be very limited and obviously I don't want it to leak when it's all put back together!

Alternatively, can I just reuse the plenum and install new gaskets? The plenum and upper and lower intake manifold gaskets were last replaced back in 2007 when the car only had 16k miles. I assume they used the revised plenum that corrects the issue of EGR gasses melting the plastic, but with the car now having 238k miles, I'm wondering if it might be slightly warped, which might be causing my leak.

I would appreciate any advice or suggestions!

 

[JGBuick]

I can recommend the ATP unit. - https://www.amazon.com/gp/product/B000C8T7X6/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

I think you should NOT reuse the original manifold as the new unit has few updated features:

- metal-cert sleeved EGR port and spacer pipe allows heat dissipation and prevents repeat failures
- heat stabilized nylon increases overall durability and resistance to heat

 

[seymourj98]

With so many miles and years and how involved the job is, personally would replace the plenum anyways, whether or not it's bad. I replaced mine with Dorman last summer and have had no issues since then, but would use the ATP plenum if I were to do it again.

I'll also second replacing the valve cover gaskets and lower intake manifold while you're in there, especially the rear valve cover gasket as it is a royal pain to access with the intake installed. I discovered after getting everything apart that the 2004 LeSabres came with the improved metal-core lower manifold gasket, but it's maybe an extra 30 minutes to install on what's already a 5+ hour job so it's worth it to do IMO. These gaskets are cheap enough that it's absolutely worth doing while you're in there.

If it hasn't been done in a while, it's a good time to do spark plugs as well. Would also suggest replacing the plastic heater elbows that go into the alternator bracket with the Dorman aluminum elbows, replacing the thermostat, replacing the fuel pressure regulator, and replacing the water pump while you're in there. There are all common failures that are much easier to replace while everything is apart. The plastic elbows will probably break when you're taking it apart anyways, might as well have the aluminum replacements on hand.

 

[02LTD]

I agree with the recommendation for the ATP UIM. As for the water pump it has nothing in the way and can be replaced at anytime. My only suggestion if doing the water pump is to use the blue Fel-Pro gasket as it requires no sealant and is more “ forgiving “ than the metal based Fel-Pro gasket. The paper gaskets that come with most water pumps are garbage.

 

[ohioriver]

Not saying you will find your part here... but there is always the GMdirect Parts site.... OEM GM parts...

Engine for 2004 Buick LeSabre | GMPartsDirect.com

www.gmpartsdirect.com

 

[mlizotte]

I did just the top intake gasket at 100,000 miles. it has 200,000 and still no lower intake leaks, or valve cover leaks yet. But I'm no expert.

 

[02LTD]

By 2004 GM had updated the LIM gaskets to a better material.

 

[jotzgr]

Just my two and a half cents: I’ve done this on 3 Lesabres (2000, 2001, 2002) in the past 3 years and used the Dorman upper intake every time. Did upper and lower intake gaskets on all three at the same time. Have not had any issues or problems with the Dorman on any of them.

 

[Chromium]

Thanks for the info, everyone. Yes, I'm going to replace the thermostat and coolant elbows while I'm in there. Water pump and spark plugs were done not too long ago.

Question: What's the preferred method for cleaning up the gasket mating surfaces prior to installing the new gaskets? In addition to carefully scraping with a razor blade, I was going to use some parts cleaner to clean off any gunk - but which one is best? Would non-chlorinated brake cleaner work? Maybe I'm overthinking it, but I don't want to leave behind any residue that might chemically react with the new gaskets.

 

[JGBuick]

Thanks for the info, everyone. Yes, I'm going to replace the thermostat and coolant elbows while I'm in there. Water pump and spark plugs were done not too long ago.

Question: What's the preferred method for cleaning up the gasket mating surfaces prior to installing the new gaskets? In addition to carefully scraping with a razor blade, I was going to use some parts cleaner to clean off any gunk - but which one is best? Would non-chlorinated brake cleaner work? Maybe I'm overthinking it, but I don't want to leave behind any residue that might chemically react with the new gaskets.

Good attention to detail Chromium! Actually, you can use some brake cleaner. The non-chlorinated is fine. Mostly, it will evaporate and not remain on any surface, so you'll be fine. I actually sometimes use Acetone and a clean rag. The "big" thing here is to cover the valve train with a non-lint towel or plastic so you are not shedding debris and other garbage into the exposed area. You don't want anything falling into that gallery!

Take your time with the cleaning and make sure the surfaces are free of old and loose gasket material. Hope this helps.

 

[Chromium]

Good attention to detail Chromium! Actually, you can use some brake cleaner. The non-chlorinated is fine. Mostly, it will evaporate and not remain on any surface, so you'll be fine. I actually sometimes use Acetone and a clean rag. The "big" thing here is to cover the valve train with a non-lint towel or plastic so you are not shedding debris and other garbage into the exposed area. You don't want anything falling into that gallery!

Take your time with the cleaning and make sure the surfaces are free of old and loose gasket material. Hope this helps.

Ok, that's what I was thinking. Thanks!

 

[2000ltd]

By the way I've just learned that ATP 106001 intake plenums no longer come with the metal-cert sleeve. I've ordered two from Amazon and one from rockauto trying to get one with that sleeve and never got one. I called ATP and they said they no longer put the cert sleeve in and use plastic that is heat resistant. Jfyi

 

[Buick City Bert]

Thanks for the info 2000, would pay extra for the metal sleeve myself.

 

[2000ltd]

Thanks for the info 2000, would pay extra for the metal sleeve myself.

This is the email they sent me about the metal sleeve when I asked if they could send me a metal sleeve seperately

 

[Buick City Bert]

When I inspected the first one I received it appeared to be insert molded, i.e. molded in place with the plastic shrink causing a very tight fit.

 

[BuickGirlFromMars]

This is the email they sent me about the metal sleeve when I asked if they could send me a metal sleeve seperately

thats hilarious. should reply that they shouldnt intentionally sell defective parts that opens them to liability

And that they should put a disclaimer only for offroad purposes (EGR deletes)

 

[2000ltd]

thats hilarious. should reply that they shouldnt intentionally sell defective parts that opens them to liability

And that they should put a disclaimer only for offroad purposes (EGR deletes)

Yeah I know. I had only bought the ATP because of that feature