84' 300SD 617 turbo- running hot? - PeachParts Mercedes-Benz Forum

btrapr · #1 07-05-2010, 10:53 AM

I bought this vehicle last November and slowly went thruogh it and done some maintenance and mods...
Cold air intake with 240D oil vapor can, EGR delete...

*The vehicle temp would rise in traffic and fluctuate periodically! the coolant was dingy with rusty color, so I flushed the radiator three times and finally after lots of rust washed out the coolant is nice and green! I put a different radiator (a few years old) and a new thermostat.

I got a layer of nasty crusty greenish/orange crud out of the hoses that had been stuck to the rubber, now it just gets gets hot! up to 200...I saw tiny bubbles in the overflow can! I do not see any sign of oil in the coolant or water in the oil that I just changed! It idles in a good temperatuee range bUT the raod trip made it climb!

ARE bubbles a sign of a leaking head gasket? sounds right to me! I am also curious because I let it run yesterday and then drove it it was not hot until I went down the road...The radiator hoses got real hard___A handheld thermometer showed 205 at the intake neck on the side of the head...but just in front at the bottom hose it was 155 degrees...could the thermostat have gotten gummed up with crap? and is it possible that the impleller on the water pump be rotted enough to slow flow? I am curious if the flow is reduced and the thermostat is sitcking could it cause these issues?

thanks in advance

btrapr · #2 07-05-2010, 11:46 AM

UPDATE! NO oil in coolant

I just tore the water pump and thermostat out and can not see any reason for a flow problem...NO trash and the impeller looks fine!

I remember seeing where someone drilled holes in the thermostat to let it fow more...Tempted to get a water pump gasket and give it a try...

I can not find the 160 thermo anywhere local...just the 180 and 195...

any suggestions or advice will be welcome

cirrusman · #3 07-05-2010, 12:19 PM

The fact that you installed an old radiator makes me think that it might have been faulty itself... Did you make sure the radiator was clog free? The 80°C thermo can be found online on many websites including on this one. And yeah, if you live in a warm climate, drilling holes on the thermo is a good idea I've heard. here's a link that can help you:
http://dieselgiant.com/thermostatreplacementandmodif.htm
Good luck!

RAYMOND485 · #4 07-05-2010, 06:19 PM

1984 300D 152K
REPLACE RADIATOR AND TAKE TOP RADIATOR HOSE OFF, FILL WITH WATER,
YOU HAVE AIR IN SYSTEM OF COOLING, HAVE CAR FRONT UP

btrapr · #5 07-05-2010, 07:13 PM

I neglected to say that the radiator I put in the car came from a car my friend, who owns an auto repair shop, turned me onto!
A year ago he put a new radiator in the car and did a lot of other things to it, and the customer parked it in her yard...SO it is a NEW radiator...still has the Behr label on the top

***I think your right about the air....Ther overflow tank was low this morning when I tore it down...The temp was fluctuating before I started the flush routine...JUST not as hot as it got this last time.

I hope that a new water pump gasket...one or two holes in the thermostat gets me back in the game! and NO AIR

thanks

btrapr · #6 07-07-2010, 10:44 AM

I put it back together after drilling a few holes as posted on D-Giant...put the water pump back on...200degrees in one mile of driving...with electric fan on...

THIS time I saw some discouraging sings...small clear beads running down the oil dip stick while the motor was running...and some TAR BALLS (oil) small beads in the overflow! SO I GUESS MY HEAD GASKET IS SHOT...at least I hope its the head gasket...

thanks for the input