Thermostat - Page 2 - PeachParts Mercedes-Benz Forum

Golden Luck · #16 10-02-2002, 07:25 PM

Thank you very much George and Hunter,

I had the t-stat replaced early this morning but before I could have a chance to read your advice, espcially paid attention on the little hole as orientation. I didn't remember where I had it faced. Is the positioning critical? Should I reopen it to make the change?

Other thing was if I have read your advice before the replacement, I would have the new belt covered more careful to avoid any possible splash, but I did pay attention for not to get coolant on the belt though. I used water to wash the coolant off the engine afterward. The old one got stretched badly may be related to the coolant splashed when the pump leaked.

I noticed the old t-stat did have a stretch mark on the bottom half of its shaft, indicating the hesitation of movement until higher temperture forced it to move further. (This was my theory of course).

One thing I found was during running, the gauge stopped at approximately 87 or 88 degrees mark, and would increase after 3 minutes or so stopped in traffic, then rose to about 100 and park there. Didn't go any higher. A great improvement I thought.

Since the temperature still risen a bit compare to what it was before the water pump replacement, I think the coolant mixture may contribute some more heat to it. I read a few threads about the coolant mixture here, that more antifreez content (or percentage) can cause the engine run hotter.

Anyway, I am happy for the cooler engine, and ready to add more freon because most of them escaped after the pressure got too high, I think ! ( I am going to learn another lesson on how to add freon a simple way next).

Thanks you very much folks, you guys have been the fantastic advisors. I love this forum, and have been learning a lot.

_______________
Golden

1994 C280, Red hot with cream interior 106K miles
2000 ML 320 Silver
1991 190E 2.3

stephenson · #17 10-03-2002, 11:38 AM

Yep ... I have a feeling that many folks have too much coolant in their systems. Second "feeling" is that many folks have less than a perfectly sealed system (bad cap, small hairline cracks in overflow, etc).

Seems like you can buy a cheap tool to check the coolant ratio ... can't remember, maybe it simply determines specific gravity of the material against a baseline.

Final thought would be that the viscous clutch could be contributing ... same issue as with the tstat - i.e. the curve for its activation is temp based and perhaps it simply is activating too late in the cycle?

#18 10-04-2002, 07:23 PM

Hi Golden,

FYI: Just replaced the vacuum hoses from the idle control valve and from the valve cover to the aircleaner and manifold.

I can feel the engine is smoother and so far, no hesitation:-)

The hose from the manifold to the valve cover was very old and did not seal well. It was crimped somewhat as well.

I think I am confirming my on theory about little things adding up.

A few more items to go. Air filter, O2 sensor, sunroof cable and an oil change.

Also, I cleaned around the engine compartment while I had the air cleaner box off. Cleaned the box as well. It may sound basic, but make certain there is no remaining debris near the intake plenum when you put the air cleaner top back on.

Regards,

Hunter

psfred · #19 10-04-2002, 08:00 PM

Golden:

The vac supply for the climate control is the green line in the engine compartment. Best thing to do first is check for bad rubber connectors on all the vac lines -- I had to replace all of them on the 300 TE when I bought it, they were all rock hard or mushy.

After that, go get a Mitivac hand pump. You can attach it to the green line and pump -- this will apply proper vac to the AC system. If it won't pump down (there is a vac tank, it will take a while), you have a leak, and you will be able to hear it as the air sucks in if you keep pumping.

The fact that the system partially works indicates a leak rather than a defective PBC unit.

I'd guess a loose line, but could be the vac servo leaking, too.

Peter

Golden Luck · #20 10-05-2002, 09:44 PM

Thank you all for the valuable advice. I will have all VAC lines inspected to see if any of them had been accidentally removed.

I found a white VAC line next to the oil filter was removed from the engine during oil change several months ago, that caused my rear headrests failed to retract.

Best regards to all.

Golden

Golden Luck · #21 10-05-2002, 10:53 PM

An update after the t-stat replacement.

Engine is running much cooler at 87 to 90 degrees, and the auxiliary fans kicked in on and off even the temperature is at around 90, and the high pressure could have triggered the fans before the coolant temperture get too high. In traffic, it rose slightly to 100, and not higher. It almost run as cool as before the water pump got replaced.

Thanks again for the advices.

_______________
Golden

1994 C280, Red hot with cream interior 106K miles
2000 ML 320 Silver
1991 190E 2.3

#22 10-06-2002, 12:32 PM

Hi Golden,

Great!

While you are at it, replace all the creamic fuses you can find. A simple but effective way to prevent minor electrical problems.

Don't assume they are good by looking at them. They get old and they go bad. Somethimes they look okay. If they are 5 years or older, or you are unsure of their age, go for it.

Best,

Hunter

PS: If you really want to go further, replace the relays over a period of a few months. They go bad and usually at the wrong time. Assuming I keep my car, that's what I'll be doing.

a2aa · #23 10-06-2002, 08:38 PM

if everything ie: belt, t-stat, h2o pump, checks out ok, then I would suggest making sure that your coolant/h2o mixture is correct. I use 60% h2o and 40% coolant
Then add Water wetter. I use it and here in Texas, can't go with just h20/coolant . Mbz are very sensitive to temp changes and you're right 105-110 degree reading is enough to crank up your reserve adrenalin. Good luck

stephenson · #24 10-07-2002, 08:21 AM

a2aa,

I have been looking for someone who can substantiate the claims from Water Wetter .... so, when you run your car without it at the exact same water to coolant ratio, it runs hotter?

There has been a lot of discussion on WW on this site and others ... and, there appears to be no independent test data - and, there also appears to be a large number of people who simply don't believe the claims ... so, your experience, if providing an audit trail of some sort, would be very helpful.

Most everyone that is a supporter has done SOMETHING to their cooling system WHILE they were replacing coolant (in addition to WW), that generally invalidates testimonials. If you have simply (and ONLY) replaced your coolant mix with a mix that includes WW and it changed the operating characteristics (i.e. it runs cooler) it would useful to all.

Thanks.

#25 10-07-2002, 08:53 AM

The use of Water Wetter may not show any noticable difference in the displayed coolant temperature. Water Wetter is useful in eliminating hot spots in the engine by preventing bubbles from isolating the coolant from the hot metal.

I use Water Wetter because Frank King, the former Technical Editor of the Star magazine, recommended it. Frank had that job for decades and was a very smart man.

Water Wetter isn't a snake oil product like Slick 50. It comes from a company who probably produce the best commercial motor oil you can buy.

BTW, Water Wetter includes additives similar to coolant so that if you tend to run more than 50% water in the coolant mix, the addition of Water Wetter will offer additional protection for the water pump, etc.

a2aa · #26 10-07-2002, 09:23 AM

stephenson---- please check your mail

a2

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