300SDL fuel leak
 

Hello! I’ve used th de forums before to get information but have never posted. I just bought an ‘86 SDL and it’s in solid shape. Needs all sorts of stuff but I can’t wait to get started.

I noticed fuel pooling on one of the motor mount arms. I learned the fuel thermostat leaks often. The leak appears to be coming from under the fuel thermo. There is a flat, almost triangular shaped mount that is RIGHT under the fuel thermo. I can see a drip every ~1.5 seconds on the right side (toward firewall) It’s possible it is coming from a blind spot on fuel thermo but I don’t think so. Any ideas?

I’ll take photos if anyone needs them to see where I’m talking about.

Thanks!

The O-ring seal in the plastic part of the fuel heater thermostat is bad. It'll still suck air after you replace it. Delete that POS and send the fuel line straight into the lift pump. You'll save yourself a TON of headaches during your ownership of the car.

I thought I recognized that problem. I did a search for the thread I did on it:

http://www.peachparts.com/shopforum/diesel-discussion/386159-leak-fuel-preheater-thermostatic-valve.html

Has some good links with photos plus more discussion.

Do you think deleting it is alright with a cold Ohio winter on the horizon?

Thanks for such swift response!

Considering that the fuel heater doesn't work until the engine has reached operating temperature, I can't see how it would make any measurable difference to cold weather performance. The injection pump itself transfers engine heat to the fuel anyway, so it isn't like the fuel is going to remain ice cold when the engine is running. On the other hand, that thermostat will leak air even when it has a new O-ring fitted and make your cold starts that much harder. Pick your battles.

Awesome. Thank you!