Overheating at idle - fan problem?
I have just started to notice if I leave my G stood idling for 5 minutes or more the temp rises to over 100
Today when I switched off the motor as it reached the top end of the temp range on the guage, coolant was spitting out of the reservour & lots of 'gurgling' noise etc. Started it up & ran it down the village & back & temp dropped to about 90.
Temp when driving is OK, only when idling does it rise & then it drops almost immediatly when on the move.
Only time it rose when driving was when doing 70 - 80 into a headwind on the A1.
Anyway, today when the temp rose due to it idling in the yard I switched off the engine & then looked at the cooling fan. The fan could be rotated by hand easilly. The fan does spin when the engine is on though.
Could this be a problem with the viscous 'clutch' on the cooling fan? I assume I should not be able to spin the fan by hand if the engine temp is high?
Any ideas?
Certainly sounds like the fan coupling to me. At that temp. it should be locked.
See:
http://www.gwoa.co.uk/index.php?name=Forums&file=viewtopic&t=4716
Price for that part number (I need a new coupling but for different reasons) about £177 plus VAT compared to £246 from Merc. stealer.
Or around the same price for 2 x 12 in Pacet electric fans inc. thermostat
Welcome to the club! I have a similar car and the exact same problem, and it is embarrassing when you get stuck in a traffic jam and the temperature keeps creeping up.
I suspected the radiator (that had been changed 3yrs ago), as the fan seemed to work correctly. I also changed the coolant (twice), and the head gasket. I have now sourced another radiator to use, when I can hopefully send this one to see if it is indeed blocked or not. We'll see...
Let us know if you have any joy with the fan coupling..
sounds like coupling, quick remedy is look behind the fan there are two metal tabs turn the fan so they locate with 2 cutouts in the pulley then bend them in do permenantly drive the fan, not good for petrol consumption but keeps your car cool. its shown in your owners manual if you have one
simon
One other small thing to check is the return hose from the expansion tank to the radiator. If it's blocked the problem is exaggerated.
If you have an auxiliary electric fan in front of the radiator and it works, the temperature would normally drop even though you may have a problem with the viscous clutch.
Or the cylinder head is cracked ...
Feel the radiator for cold areas when you are up to full temp, best way is to take the front grille off and you can feel around to tell if there are any water channels blocked. The tabs for locking the visco coupling are the grey metal spikes next to the plastic fan blades to couple it permenantly.
Feel the radiator for cold areas when you are up to full temp, best way is to take the front grille off and you can feel around to tell if there are any water channels blocked. The tabs for locking the visco coupling are the grey metal spikes next to the plastic fan blades to couple it permenantly.
Yep.........
You have been given good pointers but, shall we approach this topic methodically?
Start from a cold engine, check and correct the coolant level, if you need to, top up, do this with water. Start up your engine, monitoring the temperature gauge, top radiator hose temperature by feeling the heat emited from it and by compressing the top radiator hose, to feel how pressurised it is, during warm up. At all times taking care of your hands as you are working with moving parts!
There are two other items you need to keep an eye on. One is the interior heater, keep your fan speed on two or three, and feel if the air blows warm to hot as the vehicle warms up. You should be blowing hot by the time the temp. gauge reachs or approaches around 80 degrees centigrade.
The other is the radiator, at about 80 d/c, the top part of the radiator should start to get warm, as, should the top radiator hose.
Squeeze, the top radiator hose, this should have some light presssure in it but not rock hard. Get an assistant to accerate the throttle at about 1500 rpm to 2000 rpm and keep that steady, carefully position your hands just behind the fan cowling, if the fan is working air will be rushing around this area, if not then the likely hood is, the viscous coupling has failed.
One of the threads above mentions tags to fold to lock the coupling, I think that only applies to the Diesels, in general, not the Petrols.
By this time the engine would be fairly hot going over to overheat, switch off, and carefully feel the radiator core, if there are cold spots felt, you are looking at a blocked radiator, you can get a local radiator specialist in your area to recore the radiator at half the cost of a new.
Earlier, I had asked to feel the temperature of the top radiator hose, if this is cool by the time the temp. gauge reaches 80d/c, then it is likely that the thermostat is not fully opening up, in which case this needs renewal, before condeming your radiator.
Let us not forget, a very good pointer, from one of the threads above, whilst checking, by feeling for the temperature, feel all the hoses of the cooling system, one of the hose areas that is also pron to blockage is the bottom hose, from the expansion tank to bottom radiator, with the vehicle at normal operating temperture, all hoses should be warm to hot, if not there is little or no flow through that part.
So, there goes, hopefuly, I have not confused you, you have firstly the thermosat to check and eliminate, then, the viscous coupling to eliminate and finally the radiator.
If niether of these are condemend, then it is most probable that the head gasket is the cause, be it in its early stages. Do not be surprised if the head gasket and the other faults you were checking for are not associated.
In all probabilty, it seems that the viscous coupling is to blame here.
Thats tidied up the advice Rakesh 8) The tabs for locking the fan are present on the 300 GE petrol though, they are not obvious but there are maybe 30 spikes or 'tabs' on the pulley just behind the plastic fan, says in the owners manual to bend a few (8-10) over with a screwdriver although this is only an emergency "get you home" measure if you have a major overheat. Could be used to test the fan but once proved either way bend them back straight asap.
there are 2 opposing ones on my 230 ge
simon
Alas, I stand corrected.
Thankyou, Gentlemen.......
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I've had another look at the fan & can't see any tabs on the fan body.
There is the belt pulley, then a 'toothed' disc, then the fan.
Are these units easy to replace? Is it false economy to find a used one?