Nicholi2007

I've search the forum and see this is an issue but yet to read any solutions.

Hope someone can provide some insight....

Issue: Radiator fan revs high like a turbine.
Temperature is fine at 75.

I replaced the thermostat but for some reason coolant is not going down when I run the engine. No light on for low coolant.

W204Motorsports

Need to bleed the system, sounds like the fans are compensating for an air pocket somewhere in the system.

Nicholi2007

Thanks for the reply. Took off the cap and left the engine run till warmed up.

Heat on low fan. temp all the way up.

Problem is that fluid started to spill out.

I would have thought the fluid level would stay even.

Do you recommend squeezing the hose as air is stuck? Seems rather odd...

W204Motorsports

yes squeeze the hoses, both lower and upper, be careful with the belt spinning and try to park on an incline doing all this, usually that does the trick but if it doesn't, you will need to get the the bleeder that is next the starter on the passenger side head .

https://www.pelicanparts.com/techart...eplacement.htm

Here's a step by step if you need to get to the bleeder.

Nicholi2007

Making some progress. Heat comes on but not for long. Then the radiator fan winds like a turbine.

This time the temp gage gas jumped as high as 95. I pulled over as I was worried I might overheat the engine.

I get the feeling this is a temperature sensor issue. Thoughts?

W204Motorsports

No, if it was the temp sensor then the temperature gauge would give unrealistic values and cause a check engine light. I dont know what you mean by the fan, if its making abnormal noises then the bearing in it is damaged and needs replacing.

Im sure it's still just air in the system, 95 degrees isn't over heating, these cars runs at about 90-95 degrees, if it was 100 and over then I'd be worried. All your symptoms point to air in the coolant system.

If the hose squeezing and incline bleeding didn't work, you will need to bleed it from the bleeder screw next to the starter, make sure the engine it hot when you do so. Good luck.

Nicholi2007

To clarify, the radiator fan starts to wind up. The speed goes so fast, it sounds like a turbine or an airplane. Eventually the radiator fan speed dies down but still runs high.

Perhaps this suggests it's not getting proper signal or a sensor is out.

Thanks.

NZ-Merc

Hi,
What you need to do is full the cooling system when cold then install the cap,start the car and keep at idle Do Not remove the radiator cap (otherwise the water is pushed out) idle to 2000 rpm until the engine temp gauge is at the normal position, heater working correctly and Most importantly the top radiator hose is fully Hot then take for short drive STILL don't not remove the radiator cap.

Park the car let it cool down and then remove the cap and top up when full cold.

The fan is going due air in the cooling system, low on water and cannot conduct the heat away due low amount of water.

W204Motorsports

^Exactly, the fan is trying to compensate what the coolant can't achieve. You need to keep trying to bleed the system, the fact that you started getting some heat from the vents is a clear sign that this is your issue and not a sensor problem.

Nicholi2007

many Thanks guys, I appreciate you taking the time. I will keep at it and update!

EzE350

were you able to get the radiator ran issue resolved with recommended tricks? I am having a similar issue with E350. Radiator fan running at full speed. Almost shakes the car and it does sound like a jet engine.

Nicholi2007

Nicholi2007

It's now gone off the rails. the temperature is having wild fluctuations where the needle maxes to 120 at times. I shut off the car because I'm afraid I'll blow the engine. Oddly no check engine light.

I have no idea what to do but bring it to the dealer.

W204Motorsports

Bring it to an indy shop and tell them to bleed the coolant properly before you blow the engine, I think you've peaked your skills of trying to repair this.

Nicholi2007

Resolved it.

Here's what I did.

1. I took the cap off and squeezed the hoses while the car warmed up. Then the coolant started to rise and overflow.

I quickly put the cap on and went for a drive, Sure enough Temps started fluctuating, Anything over 95 I quickly pulled over.

The fan stayed on but temp was never about 95.

2, The next morning I opened it and the coolant was really low. I was surprised.

So that told me a big pocket of air was in there. I filled so the level was at the base of black piece in there.

I took for a drive and returned home.

3. Waited 1 hour for engine to cool down. I opened cap slowly and air came out. kept cap on but loose. Tightened it.

It's been running fine temp wise. Heat comes on fine. No crazy fan speed.

Occasionaly the fan will come on but at a low speed with no A/C on. I presume that's normal. Temp is constant 78 or thereabouts.

W204Motorsports

Good job, glad you finally resolved the issue without blowing a head gasket.

Nicholi2007

Hopefully no premature wear to the head gasket. It went to 120 a few times but I did not drive for long.

I was surprised how stubborn this was but glad it's over with.

Nicholi2007

I have had to fill the coolant twice in two days as its keeps dropping. Warning light comes on. Temp is constant. No fluctuations.

This seems unusual. Faulty head gasket?

Any idea what to look for under the hood? I don't see any leaks...

NZ-Merc

You need to have a professional look at it and check for blown head gasket or internal water leak, you will most likely be doing expensive damage.

Nicholi2007

did you read the entire thread?

NZ-Merc

Yes I have read and the entire thread and previously added detail on bleeding also experienced qualified on repairing vehicles.

Nicholi2007

They inspected and tested the system. No Issues.

He did say to check and fill when cold.

I've been filling it sometimes after an hour which may explain it.

He says filling it hot results in water evaporating.

Thanks for your input!

bbbbbbb

You might have put the thermostat in backwards and water is not flowing into the engine OR you got a defective thermostat. I'd check and verify that you put it in, in the correct direction.

Marcil802

Thanks alot . That thread was true help

davmil2002

Mine sits there all the time in summer traffic with air conditioning on. Always has. I don't know how, but make sure you've got a problem before throwing money at it is my advice.