Hi All.
Now I have the car running. 2001 series 2. I have a misfire on #3.
A compression test was done by a previous mechanic. He gave up and said it's not worth dealing with. I want to determine for myself where the low compression is from. It belongs to a family member and they really like the truck and I want to help. I've done a leak down test on my old Mercedes 6.3 v8 sometime ago. Which was very helpful in determining what was wrong. My question. What's the easiest way to get tdc compression stroke on #3? So I can run the test? I'm assuming first I need tdc on #1 then go through firing order.
Cheers John

 

Maybe put a straw down the #3 spark plug hole to find tdc. Of course easier to crank around if all spark plugs are out, so easy to check #1 that way. Possible to be 360 out, so check both positions.

 

Thank you.
I'm getting what I can only best describe as a chuffing sound from around #3. If that makes sense. I suspect a gasket leak to the outside not toward a water jacket. As Oil and coolant look clean with no evidence of cross contamination.
Cheers John

 

The center cylinders are known to blow the HG to the outside. Usually when running it sounds like a huge exhaust leak, my wife described it as a helicopter taking off. If you use a leakdown tester, blowing air out the exhaust is bad exhaust valve, air out the intake is intake valve, air out the crankcase is rings/piston. Oil in the cylinder can help seal worn rings for testing purposes. Low compression without leakdown can be bad cam lobes or rockers (never open fully allowing full compression). You can find TDC by putting finger over spark plug hole while someone turns engine (easiest with plugs out). When it tries to blow your finger off you are approaching TDC. A straw or other harmless long rod down plug hole can help determine TDC although not really required for leakdown test, just somewhere on compression stroke but preferably in top half. Borescope might help, phone usb scopes are cheap on Amazon. In all the engines I pulled apart I had one with a severely scored cylinder, like it had been run at the beach without an air filter down that one cylinder only.

 

Thanks for the tips. I'm starting this weekend.I did remove a couple of things last night. I noticed a little oil in the throttle body
I'll do the leak down and post what I find
Cheers John

 

Oil in TB is relatively normal, have you done poverty mod?

 

Having been through this recently and ended up replacing the head gaskets, it really is best to pull all the plugs, only takes a few minutes.

 

Hi
Not sure what that is? I'd love to know.
Cheers John

 

I certainly will
Thanks
John

 

Lol, I did not notice that autocorrect change PCV to poverty, sorry about that.