UPDATE:

Sorry for the delayed reply, things have been very busy around here and I finally got some time to work not the Montero today.

I got all six plugs out finally including the shredded/melted boots - that was HELL.

I did not know what an engine with no compression sounds like, I happened to see this video on YouTube and now I am certain that my engine has very little to NO compression. My motor sounds LITERALLY identical to this when I try to turn the key.


So should I even really do the compression test? Or is there a different direction I should head? Or do I still need to do the compression test to get the numbers from each cylinder?

Lastly, dumb question, but do the belts need to be installed in order to do the compression test? I removed them to replace with new ones but the new ones have not arrived yet.

 

The reason the engine in the video has no compression is because the spark plugs are removed. But there is definitely something wrong with the cylinder #4, since that one is capped with the test gauge and should under normal circumstances build up compression. Does your engine sound like this when all spark plugs are in? or when you have the plugs out? As far as the belts go, you only need timing belt to do a compression test and I hope you did not remove it yet. Make sure you have a battery charger available too, because you'll have to do a lot of cranking and that will drain your battery.

 

I thought you were supposed to remove all the plugs in order to do the compression test? Or do you remove one at a time as you check each cylinder?

My engine sounded just like that even with the spark plugs still in the car..

No I did not remove the timing belt yet I was waiting to remove all of that stuff until I knew I absolutely had to.

 

I think if you remove all the plugs it will let the engine crank over easier because the other cyl's will have no compression (due to the giant gaping hole). The only cyl that really matters is the one your tester is screwed into.. The tester seals the hole so that one should be able to build up pressure as the engine spins.

That car in the video sounds pretty bad and if yours is doing that with the plugs in that's double bad.

 

Yes you do remove the spark plugs to do compression test. As it is stated in the previous post - this is to make it easier for starter to crank the engine. If your engine sounds like the video while the spark plugs still in it - you definitely have a problem. Something went really really bad. I'm trying to wrap my head around this and I honestly can't figure it out. I can't imagine all cylinders failing so badly that you completely loose compression. The only thing that can come close to such situation is warping of the heads. Blowing both head gaskets in multiple places (6 or at the very least 4 spots) is less likely but can't be ruled out. In ether case if that's what happened you will be getting coolant and oil mixing in both of these situations. I wonder if it's possible that coolant got into the oil, but since the engine stopped running right away, all the coolant just settled down on the bottom of the oil pan. You can unscrew the oil drain plug and see if you get coolant coming out before the oil starts draining. Check that first - you do not want to whip up the coolant and oil while running compression test. Since you are set up to run compression - go ahead and do it. If nothing else, you should be able to see if the problem is limited to one bank, both banks or to just a few cylinders. But from your description it sounds like you are going to be digging in further into the engine.
Sorry about that.

 

Alright, well I will drain all of the oil out and dump some cheap oil in there to do the compression test and for the rest of the diagnosing.. once I get everything fixed I'll put better oil in.

I'll do that and the compression test and let you know how it goes.

Anyone know the proper oil weight and capacity for a 98' 3.0?

 

UPDATE

I picked up some cheap Napa 5W30 oil and a cheap filter just to do the compression test with clean oil. I drained out the old oil and this is what came out - it doesn't look TERRIBLE.... definitely not "frothy"... maybe a tiny bit of coolant, i'm not sure.

It seemed like the Hulk put the oil filter and drain plug in - I almost had to use a breaker bar to get the plug loose!

I will be doing the compression test tonight, I have been so dang busy but I am making time tonight! I will post the results later this evening.

 

Looks pretty oily but it's not super scientific or confirmation... Good luck with your test.

 

UPDATE

The results are finally in from the compression test and they are NOT good!

I have virtually no compression... this test was done on a cold motor obviously since the vehicle will not start so I expected the numbers to be low, but even for a cold motor these numbers are very low according to my research.

So! Now my options are to start tearing apart the head and checking the head gaskets/piston rings/valves etc.....

Or I can remove all the pulleys and what not to get the timing belt to check if it is snapped or not - Once I rule that out the next option is obviously to start opening the motor more.. so I would rather check the timing belt first I guess unless you guys have any other ideas??

Thanks for all the help with this guys, I really do appreciate it. This project is just taking a while as I am very busy with side jobs etc.

 

Oh wow. That is horrible... Sorry to hear that... At least you know why it isn't starting now :P

I think even in the low 100's is bad...

I don't think compression should change that much even if the engine was warm.

I think a broken or off timing belt can affect compression but again I don't know that it can do it this dramatically...

Can't you check the timing with a timing light?

I'd be more worried about deeper damage, I am guessing you will probably need to tear into that engine more but I bet Hunter knows best.