1991Jeep_Man

So, the leaking, cracked exhaust header on my 1991 XJ is about to get the boot. Come Friday (hopefully), a buddy of mine will be helping me tackle the project. This is a list of my objectives:

• Clean and paint the Throttle Body
• Disassemble, clean, and paint the intake manifold
• Polish/clean the fuel rail
• Check the Freeze/Expansion plugs
• Clean the engine block that usually lies under the manifolds
• Clean out the intake and exhaust ports

So, I have a couple of questions. I'll just list these as well.

1. Probably really easy, but does the throttle body have a gasket? If so, anyone have a part number or preference in brand?
2. I plan on pulling and cleaning all the sensors mounted to the throttle body. Any ideas/advice on this process? Also, do any of these have gaskets that need replaced when removed?
3. Will 500* paint work well on the throttle body?
4. Will 500* paint work on the intake manifold, or should I use 2000* paint?
5. Any ideas on how to clean the inside of the manifold and intake/exhaust ports in the head?
6. Finally, should I buy new bolts for the manifolds or just reuse the stock ones?

Also, any advice and instruction with the swap itself would be greatly appreciated! Thanks guys!

hi im adam

1. Your manifolds have gaskets, but your TB doesn't.
2. Let the senors soak in diesel fuel... but just the sensor part
3. Don't paint your throttle body.
4. Don't paint your intake.
5. Pressure washer imo. If you use anything flameable, take a lighter to it when you're done. if you use water, make sure its dry.
6. The old ones should be fines unless you wreck them



the thing about painting anything in your engine bay... it all has to look nice and be painted, otherwise it looks like you replaced parts. Reminds me of a ricer civic.

but thats just my opinion.

dukie564

1. yes throttle body has a gasket - replace if you remove it. I always use Felpro gaskets. You also need a new intake/exhaust gasket.
2. Search for IAC cleaning guide. TPS cannot be cleaner/serviced. IAC has a o-ring, no gasket.
3. Should be fine, but i advise against it (see below)
4. I'd go higher than 500* seeing as it's directly above the exhaust header, but again i advise against it (see below)
5. Be VERY careful doing this. Only scrape a bit out it it's really bad. If it's not terribly carboned up, LEAVE IT ALONE. You risk sending pieces of crap into the cylinders - which could cause all sorts of unpleasantries.
6. Bolts are fine to re-use for the manifolds.


Now the issue with your plan. The TB and intake manifold are aluminum. Aluminum is not usually painted, but rather anodized. This is because aluminum is very hard to get paint to adhere to due to the natural oxides that form on the surface. This is especially true if the part is going though thermal expansion/contraction (eg. your intake manifold and TB). There are ways...but they aren't cheap or easy, and there's no guarantees it will hold up (if it doesn't, it'll look MUCH worse than it did before you painted it).

http://www.ronjoseph.com/painting-aluminum.htm

1991Jeep_Man

Ah, I never would've known that. Thanks for the link and warning. I guess I will just give a really good scrubbing and make it look clean. As for the TB, I can always wait and save up for the powder-coated bored TB's that many guys here have bought. Again, thanks for the advice!