I gotchya, ya only use regular diesel not bio diesel. Im gunna check compression and let ya guy know hopefully this weekend. And I gotchya on the 6.5 i re read I have a 24v cummins aswell and that's a trick when the pump starts going to ****. About 2 years ago in summer it didn't start when it was hot outside. But this past year it has been fine.. Stupid electric bull **** but it's a good running truck and makes great power for the little performance stuff I have done to it.

i still havent gotten around to compression test my truck, but it did try driving it the other day and of course it wouldnt start at one point so just for my own humor i hooked up a strap to it and pull started it with another truck wlaha starts right up... and then when i got it back home the mercedes coolant canister was dumping out coolant but the temp gauge never got hot...

Check fuel pressure too.

Thats odd. That radiator has no cap right? Can you check for bubbles with it running? Idk.

You may have hope for low compression symptoms....

Do you know off hand what fuel pressure is supposed to be at? And radiator has no cap Im running the factory benz radiator and over flow tank. I have another block so I may end up having to pull my head off and swap all the accessories over to that block and be done with it.

Aside from anything else...
you may need to add a shim or put thicker one under the precombustion chamber.. ...having lowered the head...... also check on the correct type and thickness of your head gasket... they updated that several times .....some have different holes in them which may be important...

__________________
1980 240d ,

chain elongation, cam marks reference:
http://www.peachparts.com/shopforum/diesel-discussion/10414-help-i-need-check-stretch.html

http://www.peachparts.com/shopforum/diesel-discussion/305365-9-degrees-chain-stretch.html

evap fin cleaning:

http://www.peachparts.com/shopforum/diesel-discussion/156207-photo-step-step-post-showing-w123-evaporator-removal-1983-240d-1982-300td.html?highlight=evaporator

A/C thread

http://www.peachparts.com/shopforum/diesel-discussion/297462-c-recommendations-mb-vehicles.html

The fsm (factory service manual) should state your required fuel pressure. Procedures for checking for a blown head gasket. Etc. compression. Leak down.

Should even have a chart for diagnosis. No start at operating temp, check this. Etc

But a simple check is to see if bubbles are coming out your cooling system. In your expansion tank, in your case.

If i remember correctly you have a fsm. Mine is for my 615 or i would look it up.

I assume you have no computer chips which could respond differently due to temperature.. right ?

IF this were a small gas engine...... It would almost certainly be that the valve settings were too tight..... so it will start with the valves cold.. but once they expand... then they are long enough that compression is affected....

Seems crazy... but perhaps checking the valve setting... would be in order....
and are you using the correct specs... in inches... or mm ?

something little but basic to the physics of the engine can really cause head scratching..

__________________
1980 240d ,

chain elongation, cam marks reference:
http://www.peachparts.com/shopforum/showthread.php?threadid=10414

http://www.peachparts.com/shopforum/diesel-discussion/305365-9-degrees-chain-stretch.html

evap fin cleaning:

http://www.peachparts.com/shopforum/diesel-discussion/156207-photo-step-step-post-showing-w123-evaporator-removal-1983-240d-1982-300td.html?highlight=evaporator

A/C thread

http://www.peachparts.com/shopforum/diesel-discussion/297462-c-recommendations-mb-vehicles.html

^expert

I think you've got this backward. Hot engine, longer valve stems, looser valves, better compression. Difficulty cold starting can be caused by tight valves, that is why FSM says to adjust/set the valve clearance on a cold engine.

Hot start problems generally have to due with fuel delivery if the starter / battery are doing their thing. Glow plug relay could have a heat-soak related failure I guess. My '87 300TD had occasional hot-start problems, which were longer crank times and then rough running once started. Now I've got a #17 head with inclined injection and Greazzer-rebuilt Bosch injectors, car starts like a dream. I suspect that the injectors are what solved it for me, but cannot say for certain because so many things changed (cam shaft, head / pre-chambers, new glow plugs).

__________________
Respectfully,
/s/
M. Dillon
'87 124.193 (300TD) "White Whale", ~392k miles, 3.5l IP fitted
'95 124.131 (E300) "Sapphire", 380k miles
'73 Balboa 20 "Sanctification"
Charleston SC

No, I'm wrong, leathermang is right in that too-tight valves will get tighter on a hot engine, and may compromise compression. Sorry about that!

__________________
Respectfully,
/s/
M. Dillon
'87 124.193 (300TD) "White Whale", ~392k miles, 3.5l IP fitted
'95 124.131 (E300) "Sapphire", 380k miles
'73 Balboa 20 "Sanctification"
Charleston SC

ill check the valves before i do anything drastic like puling the motor out

This does not sound encouraging. You may have a blown head gasket or cracked head. It can be verified with a "block test kit", which looks for CO in the coolant by titration.

__________________
85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

Thats a cool method. Will have to check it out

After a cold valve adjustment, i do a cylinder leak down test to check pressure loss. The fsm covers it all. Should be done at bdc, I've accidentally turned a motor over pumping air in.

Thats one tool thats worth spending more money on, +$50.

Or pay someone for diagnosis. I do that too. At this point its $50 to the local euro shop for a guaranteed answer to the problem. So far. He also can recommend a machinist.

50 years old + and a mustache seems to be a good sign in a benz expert.