Thermostat and block heater. W123. - PeachParts Mercedes-Benz Forum

JimRockford · #1 11-12-2014, 08:54 PM

So it looks like my thermostat is stuck open, temp gets to about 40 and stays there. Luke warm heat is pumped out. I am going to change the thermostat and see if that dose anything.

Also we are getting pretty cold here in Chicago, got the block heater but have not put it in yet.

Anything I should know about installing the thermostat?

As for the block heater, looks like if I take off the intake and exhaust I can get to a plug on the side of the block. Or is there another way?

Thanks guys!

jay_bob · #2 11-12-2014, 09:23 PM

Thermostat, you will have to drain about a gallon of the coolant to avoid a flood. The drain plug is under the radiator, it is a red thumb screw.

Be very gentle with the housing bolts. I would use some AeroKroil on them first and be very gentle breaking torque. Better to use a 1/4 drive ratchet, and very gently bump the end of the handle with your hand.

Other than that it is pretty straightforward. If you have green coolant, go ahead and drain the system and refill with the proper Zerex G05 / distilled water mixture. 1 gallon each mixed together for 50/50 proportions.

Block heater, your car should already have the heater itself. It is located on the right side of the block, and if it has never been hooked up it will have a knurled cap on it. Best seen from below. You might need a new cord if your cord is original.

JimRockford · #3 11-12-2014, 10:15 PM

Thank you jay_bob on the play by play for the thermostat. It looked pretty simple but you never know, looks can be deceiving.

As for the block heater, never had one installed since it was a southern CA car. I bought a kit for it, cord, heater and all. I see the block plug on the pass side but all the pipes for the intake and exhaust look like they would be in the way to really get a good grip to take that plug out.

jay_bob · #4 11-12-2014, 10:38 PM

Have a look here for block heater install

THE Definitive Block Heater Coolant Plug Removal Thread

leathermang · #5 11-13-2014, 07:27 AM

Distilled water is not necessary.....has no advantages in this case and of course costs more...

jay_bob · #6 11-13-2014, 07:47 AM

$1 for a gallon at Walmart
Cheap insurance especially if you have tap water with high mineral content.

leathermang · #7 11-13-2014, 08:16 AM

Quote:

Originally Posted by jay_bob

$1 for a gallon at Walmart
Cheap insurance especially if you have tap water with high mineral content.

Paying for something you don't need is not cheap.... we just don't need to promote this myth.... plenty of other myths floating around....

strelnik · #8 11-13-2014, 08:36 AM

Quote:

Originally Posted by jay_bob

Be very gentle with the housing bolts. I would use some AeroKroil on them first and be very gentle breaking torque. Better to use a 1/4 drive ratchet, and very gently bump the end of the handle with your hand.

X2!

It does not hurt to tap the bolt heads squarely, not too hard, several times to loosen any rust and/or other stuff between the threads on the bolt and the housing.

This component is often weakened by thew effect of antifreeze (or lack of it) acids and the effect of steel next to aluminum.

Some people pass a little heat with a 0000 tip torch directly on the bolt head, then tap, and return later to loosen.

This is, to my knowledge, the only really tricky bolt on the top of the engine.

Others can chime in if they want, but on the top, I have not seen any other really tricky ones.

jay_bob · #9 11-13-2014, 10:18 AM

The 123 water pump bolts are like that too. Similar size bolts, same issues.

JimRockford · #10 11-17-2014, 09:59 PM

Thank you all for your input with this.

It dipped down to 9 deg here in Chicago and Klaus fired right up even without a block heater installed (as of yet).

I am going to do a big order with Pelican and hopefully get this all done within a few weekends.

fahrvergnugen · #11 11-18-2014, 01:46 PM

Quote:

Originally Posted by leathermang

Distilled water is not necessary.....has no advantages in this case and of course costs more...

It IS necessary in some case, but not with these engines I agree. The VW Wassserboxer needs it, mostly because the aluminum head tends to rot where it touches the steel piston sleeve. Some engines definitely benefit, and if you have very heavy water, it damn sure wouldn't hurt. BUT, with these engines, I think it is indeed overkill.