Mercedes-Benz Forum banner

1 - 5 of 5 Posts

·
Registered
1987 300SDL
Joined
·
129 Posts
Discussion Starter · #1 ·
I bought a 1987 300SDL on Monday. Absolutely love it. 217k and runs beautifully, I want to experiment with biofuels with it.

I changed the coolant last night, and I couldn't get the thermostat/water pump to circulate the coolant throughout the engine to allow me to add more, but it eventually did after driving it around the block (I had to stop once because it hit 100C pretty quickly), but no problem anymore, stays at 80-90C consistently. It didn't have a problem before (maybe slightly higher temps), but I don't know when it was last done and for my own sake want to perform routine maintenance now on it.

Anyway, here's the problem: if I turn on the defroster and have the temperature set at hot, air comes out fast with no problem and heats up after a minute or so. If I turn on the fan, air comes out of the defroster vent and at a low rate through the driver side and passenger side vents, but nothing out of the center vent. If I set the temperature to cold, air comes out of the same places, but now at a very low rate from the center vents as well. The passenger compartment vent blows fine but at ambient temperature, seems like it's on high no matter what. I've tried changing the fan speed, going from setting it to auto, it doesn't seem to matter. Also, when it's on I hear a metal-y hissing sound, kind of hard to describe. When I put the key in the start position, as well as when the car is running, I hear a hissing noise near the blower motor, and if I go to the engine in the front on the passenger side I hear a hissing noise there as well, almost sounds like something is trying to relieve pressure. Heater core?

Any ideas, or a thread with the same/similar information? I couldn't find anything like this in the search.

Thanks in advance!
 

·
CH4S Admin , Outstanding Contributor
1985 500SEC, 1991 190E 2.6.
Joined
·
43,815 Posts
Please click 'User CP' on the top tool bar, and complete your profile with a location and model of your car.
It makes it easier for members to offer advice. MB produced different, and region / Country specific versions of our cars.

Welcome, to take advantage of all the forum features, please re visit the 'Welcome to the Forum' tutorial sticky on top of the W126 page, as well as the two DIY stickies.
It will show how to search the forum (3 words min.), and has a link to the Russian MB site where you can run a VIN#.
Cheers
Attache
 

Attachments

·
CH4S Admin , Outstanding Contributor
1985 500SEC, 1991 190E 2.6.
Joined
·
43,815 Posts
Make sure you use the right coolant (do a forum search), and not the green/blue stuff.
 

·
Registered
1987 300SDL
Joined
·
129 Posts
Discussion Starter · #5 ·
I've been going through posts in my spare time, looks like I'm going to take off the dash and check out vacuum lines/vents to see if there might be any leaks or such.

The previous owner said it was changed to R134 and probably needs a recharge, so I'll throw $7 that way and see if I can't make it any cooler. Once I do that and the coolant flush, I'll give it a nice oil change and change the brake fluid. After a few hundred bucks in repairs I'll have something 10x nicer than what I bought :)
 
1 - 5 of 5 Posts
Top