I picked up my 2000 cherokee with 166k miles yesterday. As I was looking it over and test driving it, everything seemed to be ok. It did run a little rough but from what I told it sat for a while(no clue how long)

There was no CEL as I had it warming up and when I drove it before purchasing. After I bought it, I drove it for about 10 miles and everything was good. I parked it for about 2 hours and drove it again and the CEL came on.

It also likes to flash.. I knew it was a misfire as soon as I saw that. Got my scanner out and I have a misfire in cylinder #4.

I did a compression test:

1: 150
2:145
3:30
4:30
5:150
6:150

As I was doing the compression test on #3 and #4 I could hear air escaping somewhere as I was cranking it over. I thought the tester was loose but that was not the case.

My question is how should I approach finding/ fixing this issue. Any help would be appreciated.

Thanks!

 

Oh man, you're not going to like what you read over the next few hours.......

Blown head gasket or cracked head. If you just bought it from someone you may become very, very angry with them soon...... If you have any kind of a warranty you should invoke it promptly.

 

no warranty. If its just a head gasket Im happy. I am in the garage as we speak pulling the head off. As of right now, I don't see signs of the famous head crack I read about earlier.

 

If you're pulling the head you may as well replace it with the newer version to save yourself the trouble later on.

 

I think you should go into the garage and pull the head.

If it were not an 0331 it would be a no brainer it's the gasket. I normally take the cheapest rout myself, but Southside has a point, 160K on an 0331....

 

What is the price that I would be looking at for the newer head. I already have another money pit car haha. I did only pay 750 for this cherokee though

 

Head gasket it is! Got the head off and there was nothing between 3 and 4

 

Unless you're a gambler, I would want to make sure the mating surfaces are straight before tossing a gasket at it. You can't be too careful when dealing with this type of issue. It's a lot of labor if you have to do it twice.

 

Do yourself a big favor and have the head checked for cracks and to see if it's warped.

 

^^^^ Absolutely!

 

^^^^ Take it to a reputable machine shop!

 

I'll gamble with this car. I looked everything over not like that is saying much with the naked eye. I'm in the middle of a complete build on a different car.

 

You might check if it's flat with a good straightedge and a feeler gauge. Maybe someone has specs handy. If you can slide a .006 under the straightedge you might want to have it more flat. (Surfaced). They could magna-flux it for cracks affordabley if the valves are out to surface). You could change the valve stem seals. With the valves out you could lap the valves with some compound and a reversible variable speed drill and a short piece of fuel line.
Like I mentioned, I'm pretty cheap, but that above I'd probably do.

Oh...You can set it with the ports up, and carefully put diesel or kerosene in the ports and look at the seepage/leakage. Just a little seepage/discoloration of the deposits around the valve seats is what you want to see. Any flow or dripping probably means that needs a new valve or grinding. Don't mix up the valves. Yse a cardboard box, 12 holes in a flap with a forward arrow.

 

Appreciate all the replies!

 

Keep us posted on how your gamble plays out and in the meantime keep a close eye on the coolant level in the overflow bottle. The drop in the level will be your first clue that you lost the bet.