W210 overheats - Page 2 - PeachParts Mercedes-Benz Forum

engatwork · #16 08-28-2011, 07:38 AM

A couple more questions.

You did install the new thermostat in the correct orientation?

Quote:

Sometimes the temp indication jumps a bit.

sensor/connection bad?

Fishnchip · #17 08-28-2011, 08:52 AM

To get all the air out, take out the plug from the top left side of head located behind upper radiator hose. Fill with coolant until all air is out.

208benz · #18 08-28-2011, 09:51 AM

The thermostat should be installed corrrectly. There is a notch to make it dummy proof. It can only go in one way.

chasinthesun · #19 08-28-2011, 10:42 AM

Its a problem I had identified on a radiator before,I did everything I could to get the car to cool .The end result was found by taking the radiator down to a shop for service,they took the tanks off and found the radiator was unservicable .The job requires them to rod out the gunk that settles over 20 plus years in a long unserviced radiator ,they then put the tanks back on ,all for $85.They found a radiator out of their 1000 plus inventory that was good to go.

208benz · #20 08-28-2011, 11:15 AM

Can the radiator be checked or tested?

TMAllison · #21 08-28-2011, 11:17 AM

My 99 does not have the coolant port where the upper hose enters the cyl head. I believe it was deleted in early 98.

I would suggest removing the rad end of the upper hose and filling the cyl head/hose with coolant until you can't get more into it. Is difficult to "burp" these.

Your fan clutch should be engaged as soon as you get off the highway when coolant temp hits +95C. Should lock up and howl like a 747 on takeoff when you increase RPM. If you turn the key off (when overheating) and the fan continues to free spin it is probably bad.

Monitor coolant temp using the CCU while driving. Press and hold REST, use AUTO buttons and toggle to screen 7(?). Idiot gage has a designed in dead spot where it doesnt report correct temps between 95C-105C. When temp exceeds 105 gage will suddendly jump up and begin reporting accurately again. CCU will always report correct temp.

chasinthesun · #22 08-28-2011, 11:34 AM

No ,I cant see how ,its kind of like an exploratory operation on the radiator,you may have flow running thru the radiator but not 100% the way it was designed.It maybe the thing that youll never have to do again for the life of the car.Its 2 problems you generally like to stay away from ,Hot Motors which equals Hot Transmisions ,both are car killers in the summertime .I usually start with this service if Ive found good pressure at the top hose,meaning a flowing thermostate at running temp and working fans, if electrical. Call your local radiator shop and describe your issues ,they might also have your radiator on the shelf ,rebuilt and in stock.

208benz · #23 08-28-2011, 12:05 PM

TMAllison - I would suggest removing the rad end of the upper hose and filling the cyl head/hose with coolant until you can't get more into it. Is difficult to "burp" these. - This is exactly what I did. Was able to add atleast 1/2 gallon of coolant into the upper hose. I added exactly what was drained from the system after thermostat replacement. 1.5 gallons total.

Your fan clutch should be engaged as soon as you get off the highway when coolant temp hits +95C. Should lock up and howl like a 747 on takeoff when you increase RPM. If you turn the key off (when overheating) and the fan continues to free spin it is probably bad. - fan spins freely when cold, once the engine gets hot the fan will stop spinning as soon as I shut the engine off. Seems like the clutch is working. But I will do the 747 test after the hurricane passes.

Monitor coolant temp using the CCU while driving. Press and hold REST, use AUTO buttons and toggle to screen 7(?). Idiot gage has a designed in dead spot where it doesnt report correct temps between 95C-105C. When temp exceeds 105 gage will suddendly jump up and begin reporting accurately again. CCU will always report correct temp. - great idea, gonna try this too

208benz · #24 08-28-2011, 03:23 PM

Monitor coolant temp using the CCU while driving. Press and hold REST, use AUTO buttons and toggle to screen 7(?). Idiot gage has a designed in dead spot where it doesnt report correct temps between 95C-105C. When temp exceeds 105 gage will suddendly jump up and begin reporting accurately again. CCU will always report correct temp. - great idea, gonna try this too

Took it for another highway drive and tried the above as described above by TMAllison. It indicated almost exactly as described and accurately.

The needle is stable at 95, the CCU display will continue to increase to 102, at this point the needle will bounce for a bit at 95, then begin to climb in temp in conjunction with the CCU display up to 120. At this point I turn on the heat.

Also for the first time the temp went beyond 105 while driving in town with a/c off. It has been stable at 95 during all other test drives in town. 75 deg outside.

engatwork · #25 08-28-2011, 04:49 PM

Quote:

The car wants to overheat on the highway only.

The engine is loaded at highway speed, creating more heat.

Quote:

The needle is stable at 95

That is where our gold E300 was today on a 80 mph trip to Macon and back.

A little background with it. Earlier this summer it would creep up to around 105 dF and it had begun to lose coolant. I found a crack underneath the upper neck on the radiator and installed a new Nissan brand radiator. The car is showing around 225k miles. I installed a new water pump about two years ago when I replaced the head gasket.

When I pulled the radiator and condenser out I found the condenser plugged up on the outside at least 30%. The car had always run a little hotter than the silver E300.

About the only thing you got left is the water pump/radiator and pluggage of the condenser.

TMAllison · #26 08-28-2011, 05:06 PM

Having repalced the spilled coolant when replacing the thermo does not tell you it is correctly filled; only that you repalced what was lost........

If it was mine, I'd pull the rad cap, let it get hot and see if it wanted to burp again (jack the nose up 6" off the ground) or would accept more fluids. Shouldn't get much more than 100-105C with the cap off if its full of coolant and the WP is working as there is no pressure present to increase temps beyond boiling. Its easy to get fluid out of the rad, I'd flood it til it overflowed.

If temps soar with the cap off, it ought to mean that fluid isn't circulating properly and whats sitting in the engine is therfore working overtime and overheating.

An IR Thermo would be a fun tool to play with to help figure out whats happpening in that event.

208benz · #27 08-28-2011, 08:55 PM

If it was mine, I'd pull the rad cap, let it get hot and see if it wanted to burp again (jack the nose up 6" off the ground) or would accept more fluids. Shouldn't get much more than 100-105C with the cap off if its full of coolant and the WP is working as there is no pressure present to increase temps beyond boiling. Its easy to get fluid out of the rad, I'd flood it til it overflowed. - I tried this, the temp maxed out at 96 on the CCU display & temp gauge & held steady. Jacked it up 6", rocked the car, squeezed both upper and lower radiator hoses to maybe create some flow to push air bubbles, let it run for a half hour or so, shut it down, coolant level did not change, temp did not change.

An IR Thermo would be a fun tool to play with to help figure out whats happpening in that event. - I have one at work, will bring it home tomorrow, where should I measure temperature?

Where should the coolant level be?

Thinking outside of the box. The transmission was replaced at the end of July. I drove the car for 3 weeks and approx 1000 miles with no issues. Can this have something to do with the problem?

GregMN · #28 08-28-2011, 09:03 PM

From what I have read on this thread, you need a new radiator.

208benz · #29 08-29-2011, 09:55 AM

I can get a Behr for $275

208benz · #30 08-29-2011, 10:15 AM

I read somewhere that people are using Zerex. I always use MB coolant, but its pricy. Is it ok to use Zerex?