I have a 2000 3500 Ram Van with a 5.9 in it. One cyl has no compression and a few others are low. My question is where to start. What could cause no compression in a cyl? A broken connecting rod? And how about low compression? I cant see an obvious leak in the head gasket but I cant say I've used the van a whole lot recently. It used to belong to a band I was in and I'm thinking of resurrecting it. Any advice to help me on my quest for Rock would be great.

_G

 

To begin, how many miles are on the engine? Could just be knackered. Sometimes the speedo lies, so hopefully you have a CarFax.

Don't ever trust, don't ever trust the speedo -- it lies. - Queensryche 1988

(OK, so it was needle - now I lied.)

 

I think its got about 150k...but i have a hard time feeling like this motor cannot be ressurected. Unless there's cyl wall damage or some damage to the block...

I think im going to start with pulling the valve covers and then the heads. Hopefully its carbon build up causing one of the valves to stick...

-G

www.chrismichetti.com

 

some thoughts:

post the cylinder #s and pressure reading...some relationships may suggest a head gskt....ie adjoining cyl's both low

did you do a "wet" and "dry" reading? simple just add some oil into cyl..will help ID if a ring issue...

also a cylinder leak down test... shop air is attached to gauge flex hose .... applying pressure you can get a good idea where pressure is leaking....ie hissing air out throttle would suggest valves, oil fill cap sound would have you look a piston sealing.....

PS: let us know if its been sitting awhile

 

The van has definately been sitting a while. Probably about 2 years unused. The dead cylinder issue is the reason we stopped using it. But I've also learned the hard way to not be too trusing of what the dealership says. Caught them on a few things so...Im not giving up on this engine.

My question is this--Do I need to pull the motor to change out the head gaskets (assuming thats what the issue is) ? In those big 15 pass. vans it looks like a real pain in the ***...

-G

 

Nope, between under the hood and going through the back you can get to everything you need to get to.

 

ok, so I noticed leaking oil from under the valve cover gasket but this wouldnt cause a loss of compression would it? Im going to hold off ripping the heads off until I get the cat converter fixed (someone sawed it out of the exhaust). That way all I have to focus on is restoring the engines strength. On that tip, the dealership wants WAY too much $$ for a new one--has anyone just gone with a universal cat converter and some clamps a la summit?

Thanks,
-G

ps, the od reading was 195. Mostly hwy miles as it was my bands touring rig for 4 years. Gotta love I-70, I-80, and I-90.

 

i wouldn't worry about the cat until you get the motor fixed and the van running. otherwise, you may be wasting a bunch of money. the cat is not important right now and the leaky valve cover has nothing to do with your compression problems.

considering that its also got a dodge transmission in it, you may very well be looking at an engine repair that could cost far more than the van is worth. it could be head gasket, or it could be heads.

start with a compression test on all cylinders. write the numbers down.
remove the heads and head gaskets and look at them.
if the heads are cracked, you need new heads.
if the heads look ok, then take them to a machine shop for inspection/rebuild.

its probably not a rod or crank or piston problem. those would knock like hell.
you can't see head gasket problems unless you have overheating or water in the oil.

head gaskets only will cost you a couple of hundred.
rebuilding heads will cost you a few hundred.
new heads off ebay several hundred.
new cat from dealer will be several hundred. don't do that.
new universal cat is 1 or 2 hundred. don't do that until the damn thing runs.

 

After you ARE ready for the cat. converter, don't make the mistake of buying too little, especially if it needs to pass an emissions test. Stay away from those short, universal cheapies because they don't have sufficient "guts" to do the job. They work fine until the idle part of the test and because they have minimal guts they cool off rapidly, the readings skyrocket and you fail.

Had this problem on an '89 with duals, one side had a cheapie converter.
The guy running the test was also a muffler shop (and had seen all kinds of failures due to short converters) so he was good enough to nurse it through the test and it just squeaked through. He held it at a very high idle for about ten minutes before the test (to really heat things up), then did a preliminary test (off line) to be sure it had a chance of passing. Not many shops are going to be this sympathetic towards old stuff and will just let it fail.

In Ontario, the emissions test is required every two years and the numbers get squeezed everytime making it more and more difficult to pass. Dec 2010 is the next challenge and I'll be installing new longer converters from my "buddy". He says about $150 ea will cover it (I install).

Have had problems in the past, never had a clearer understanding of what the problem was 'til now. Engine runs fine and uses very little oil.

EDIT: Don't know if I should really reveal this, but here goes. If you are very close to passing the test yet still fail, a few things you can do: retard timing slightly, re-adjust idle back to 750 RPM or whatever, disconnect the vacuum advance. Never had to do any of that last time on the '89, but have on other vehicles in the past to get through it OK.

 

All of what you said is fairly common knowledge. You can sleep easy tonight, there won't any black helicopters circling your house.