Hey guys,

New owner of an old Cherokee (like literally about 3 days). One of the big draws for me was the number of posts I saw about how easy it was to work on these things. So when the mechanic I had looking the thing over quoted me about $1,000 to replace a cracked exhaust manifold, I started thinking it was time to get my hands dirty.

I have a few questions/concerns I was wondering if you guys could help me with:

1. The bolts holding the manifold on are really gunked up and the mechanic said that we have to be really careful removing them because if they shear off that's it, you can't replace them. Is there anything to do to make this easier other than dowsing the thing in WD?
2. I'm very new to working on cars, but this seems pretty straight forward, can a newb really tackle it?
3. I've seen these replacement manifolds on amazon for like $130. Is he totally scamming me or is that not where to get parts?

 

APDTY 785207 Exhaust Manifold Kit (Tubular Design With Flex Joints)(Includes Gaskets) For 1991-1999 Jeep 4.0L Engine (33007072, 4883385) https://www.amazon.com/dp/B00BMZU90I..._ltpgxbJ9ZKXXG

This is the manifold I used

Dorman 03408 Exhaust Flange Hardware Kit https://www.amazon.com/dp/B00068PTHK..._9tpgxbTWH1JWH

And these are the bolts. I just reused the washer. They fit perfectly, no leaks or anything.

 

Is that mechanic's name Ben Dover ??

 

where do you live, heck I'll do it for cheap if you are near by

 

I replaced my exhaust manifold this past fall. It was not complex, just very time consuming and I needed another set of hands. I would not attempt this unless you have help. The intake and exhaust manifolds are bulky and just having another set of hands to help hold the things is critical.

About a week before attempting this job, I hit the manifold bolts with PB blaster. Again. And again. And again. And again. Drove the car etc. Your mechanic raises a valid point - if you shear off the bolt, prepare to have it towed in for repairs. $1000 seems a bit steep so I'd ask around for estimates if you are uncomfortable doing it yourself.

I bought my replacement manifold from rockauto but the P/N was the same on amazon.

Hit up youtube and watch some videos on replacing the exhaust manifold and decide if you want to tackle it yourself. I ultimately decided to replace mine because winter was coming and I didn't want to gas myself out with the windows rolled up.

 

WD-40 sucks.

Use Kroil or PB Blaster.

 

I've replaced my exhaust manifold 3 times in the last 6 months start spraying them down with pb blaster and when the weekend cones take your time and do it right and when you go to reassemble it use some never seize on the bolts so they come out the next time

 

Well you didn't pick the easiest job to start with but it's very do-able for a beginner with some patients.

Soak every bolt with PENETRATING OIL everyday for a week or two before touching them. WD-40 is not penetrating oil, get some pb blaster. Don't skip a bolt cause it's hard to reach because that will be the one that breaks.

Defining watch some YouTube videos and do your research, it will make the job go much smoother.

Also you may want to replace your motor mounts while your at it. Bad motor mounts can cause the exhaust manifold to break. Also many people recommend doing the transmission mount at the same time as the motor mounts.

 

One thing that helps with these is to spray with PB blaster and then drive it daily going through heat cycles spraying daily (while cold) and trying to move the bolts just a little bit after a few days then spray again.


The heat will help to an extent like using a torch to heat a stubborn bolt at times in some apps.

 

Maybe I got lucky put I didn't PB blast any of my bolts and they came right out no problem. I did do it with a warm engine though.

 

My jeep is relatively rusty underneath on bolts, and my manifold bolts came out no problem. Did have to sawzall the old downpipe connector bolts though. Good luck!

 

The trick for me seems to be soaking the crap out of the bolts for a week or two (PB Blaster). Clean the bolts of any loose rust and debris before putting a socket or wrench on it.

Then, I will try to initially "crack" the bolts loose. If a bolt starts to strip, STOP AND BUST OUT THE HEAT before it is too late. If you are approaching the point of the socket slipping and rounding the bolt head, you may want to consider alternating between tightening and loosening the bolt. This can help to break the rust that is seizing the bolt in place.


Once you break the rust bond and the bolt starts to turn, use tons of PB Blaster to help the bolt loosen even more. Even if the bolts are turning freely, I have had bolts seize halfway when backing them out.

Make sure you have brand new bolts on-hand, and use anti-seize when reinstalling.

It is not that involved, and there are tons of how-to guides and videos available, like this one;

 

God I had almost forgot about that. I had to do the same.

 

The key is to go from the bottom. My bolts came right out.