Remedying a warm 300D Before Atlanta Summer - Page 4 - PeachParts Mercedes-Benz Forum

My Stuff Owns Me · #46 04-01-2018, 01:39 PM

Quote:

Originally Posted by MongooseGA

This isn't a bad idea. My fan does turn with ease by hand, what would I be looking for to tell if that's the case?

Fan clutches are cheap and easy, and with 300k+ on the car I think I'll go ahead and just do it anyway since I haven't in the 50k I've owned the car.

It is not supposed to turn easy by hand. It should slip some when accelerating at normal temperature so it uses less HP.

Make sure that the fins on the clutch are clean or the coupling may not get hot enough to work as it should. Also check if there is any looseness in the bearings when moving the fan with your fingers.

If this link works it will have the Viscofan description and testing. http://www.startekinfo.com/StarTek/outside/12265/disc_2/program/123avi2.htm

My Stuff Owns Me · #47 04-01-2018, 01:57 PM

Quote:

Originally Posted by MongooseGA

I see. So assuming the ambient temp isn't requisite of using the AC (just cool air blowing has been sufficient so far this year) then the engine shouldn't have any need to use the aux fan... Am I thinking this correctly? Furthermore, there would be no signal for the fan to ever turn on without the AC compressor engaging, right? Does anyone ever bypass and add in a manual on/off switch for it?

If that's the case, then I'd definitely have something wrong as I can't imagine I should be dealing with escalating temps when we're still in windows-down weather.

A manual switch can be installed in parallel with the refrigerant temperature switch located on the receiver/dryer. It is easy to attach because the switch has 1/4" spade connectors and there are adapters.

My Stuff Owns Me · #48 04-01-2018, 02:01 PM

Quote:

Originally Posted by leathermang

The wrong water coolant mix ratio can also eat through the heater core....
there is a test one can do with an OHM meter...

How do you use the ohm meter to do this?

My Stuff Owns Me · #49 04-01-2018, 02:23 PM

Quote:

Originally Posted by MongooseGA

Gotcha. So, in essence, patching that tiny leak alone could potentially have a positive impact on cooling efficiency.

Good to know!

The pressure will raise the boiling point. It will not make the engine run cooler.

My Stuff Owns Me · #50 04-01-2018, 02:27 PM

Quote:

Originally Posted by MongooseGA

Mount an over-flow and ditch the expansion tank altogether?

Well, now that I think about it... I guess that would work.

What's the point of an expansion tank vs overflow tank anyway?

The preferred thing would be to keep it original.

I think that the design intent of the overflow tank is to keep the system sealed. Less oxygen to the coolant means less rust.

My Stuff Owns Me · #51 04-01-2018, 02:35 PM

Quote:

Originally Posted by MongooseGA

I'm still undecided on the flush. I'm reluctant after reading stories of the flush ending up being detrimental, springing leaks etc. I know it only shows to point out an already-bad system but...

The car did fine yesterday. Operating temps stayed 85-90*, and when in rush hour traffic it came up to maybe the upper 90s. Seems like that's about spec for what these should be running.

A chemical flush is only necessary on abused systems or if you see a film of oil. When I flushed mine I disconnected the lower hose and a heater hose and flushed with plain water through a garden hose. There is a drain plug on the bottom of the engine.

leathermang · #52 04-01-2018, 05:20 PM

Quote:

Originally Posted by My Stuff Owns Me

How do you use the ohm meter to do this?

Stick one end into the coolant and the other to the engine/chassis ground..

MongooseGA · #53 04-01-2018, 05:32 PM

I ended up going with a radiator/tank set up the same as OEM. The fans are all working properly as well; I can attest that the aux fan did continue running after shutting the engine down for a bit.

Temps were in great shape today. I drove it hard with the AC running, left her running, everything seems solved for now.

leathermang · #54 04-01-2018, 05:46 PM

Those Mercedes Engineers... sometimes they got it right.....LOL

Diseasel300 · #55 04-01-2018, 08:21 PM

Quote:

Originally Posted by leathermang

Those Mercedes Engineers... sometimes they got it right.....LOL

Isn't that the truth? Amazing how correctly identifying and correctly remedying the problem can make something operate as intended.

leathermang · #56 04-01-2018, 09:29 PM

Quote:

Originally Posted by Diseasel300

Isn't that the truth? Amazing how correctly identifying and correctly remedying the problem can make something operate as intended.

It would be interesting to know how much for each feature on our cars.. over the years...was spent in time and money on R and D.....

tangofox007 · #57 04-01-2018, 11:37 PM

Quote:

Originally Posted by My Stuff Owns Me

The pressure will raise the boiling point. It will not make the engine run cooler.

If boiling doesn't have a negative affect on cooling, what's the point in raising the boiling point?

leathermang · #58 04-02-2018, 02:50 AM

Quote:

Originally Posted by My Stuff Owns Me

The preferred thing would be to keep it original.

I think that the design intent of the overflow tank is to keep the system sealed. Less oxygen to the coolant means less rust.

Almost right. It is designed to keep the system sealed AND FULL even though the liquid expands when hot... and expel the air.....because liquid is a better transport medium of heat than air... and systems can have ' air pockets' like the burping required of many of our cars in order to fill the coolant system indicates.......
So all things considered.. like TangoFox007 said... avoiding boiling is critical to cooling the engine....