My 1985 300D is due for a valve adjustment, which I would like to do on Sunday. The weatherman says it might not get above 30 degrees that day. Will the low temperature throw off the adjustment?

Right now I am at 17,500 miles since my last adjustment. Should I do it now or wait for warmer weather?

I would wait just because I don't like frozen fingers. I think you should be fine adjusting the valves while it's that cold though.

__________________
1985 300D Turbo ~225k
2000 F350 (Powerstroke) 4X4, SWB, CC, SRW, 6spd ~148k
1999 International 4900, DT466e (250hp/660 ft/lbs), Allison MD3060 ~73k

Get a good high output space heater from Wal-Mart or some other place, and run it in your garage (If it's not gas ) for a few hours and enjoy a warm work area.

I believe I would wait till you experience warmer conditions - stays above around 50 dF.

How many miles do you put on it a month? Probably won't hurt to go another month or two if you are talking 1000 miles/month.

__________________
Jim

If I had a garage instead of a three-sided shed, I would 82-300td's advice, but I think I'll wait. I don't drive that much, maybe 1,200 or so a month.

Thanks for the help. Now I can drive without feeling guilty about my valves.

Hello Everyone
Data to think on.
Almost all automotive repair operations are developed in a test lab.
The mandated ambient lab temp for all OEMS; that I know of, is 70 - 74 F...
I know this applies to all GM + subsidiaries, FORD + subsidiaries, DaimlerChrysler, Asian, British and most if not all European auto makers.


A variation of four degrees is tolerable, but must be noted and signed off by the engineering team.
A variation of ten degrees is not tolerable, but can still be signed off by the engineering team.
Anything beyond that and just the ambient temp can throw the valve lash off by 3-5K depending upon skill and luck.

My personal preferance is 60 - 80F.
Below 60F my hands get cramped, and over 80F you can get correct lash but it is a PITA.

__________________
ASE Master Mechanic
https://whunter.carrd.co/

Prototype R&D/testing:
Thermal & Aerodynamic System Engineering (TASE) Senior vehicle instrumentation technician.
Noise Vibration and Harshness (NVH).
Dynamometer.
Heat exchanger durability.
HV-A/C Climate Control.
Vehicle build.
Fleet Durability
Technical Quality Auditor.
Automotive Technical Writer

1985 300SD
1983 300D
2003 Volvo V70

https://www.boldegoist.com/

You can adjust valves on a cold or warm engine, within limits:



So you could run the engine to get it within the specs. even if the outside temp is 10 deg. F., but you should be Ok to wait a week or so for warmer weather.

__________________
1984 300SD 326,997 miles and counting . . . No wait, my odometer is still dead

20C = 68F this is the minimum temp for cold adjustment.
There is a correction factor noted at the bottom.
I am certain that it is useless at 10 - 20F

Please remember that this temp is not achieved in an hour or two.
You do not drag in a -40F vehicle at 8:00 AM and adjust the valves at 12:00, a stable temp is a 24 hour (an over night) temp

I agree: Wait a week or so for warmer weather.

I don't think the valves will mind too much, but the valve cover gasket isn't going to like it when you give the valve cover the slap (to seat the gasket). My vote is to wait or pay, then put the job on your fall get-ready-for-winter worklist. Doing it in the fall will help the winter starting, too.

__________________
daBenz - 1970 220D