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Engine getting hot

300-24's can sometimes run a bit hot... mine is the same too an ive changed radiator, thermostat + loads of bits. Always been the same..

Yesterday was fairly warm too?
 
I'm pretty sure the early 300-24 engines have a bit of a reputation for liking a head gasket..

Heater matrix shouldn't affect running temperature or overheating.

Cooling systems on these cars are very, very basic. It's just a load of water/coolant pumped around a block and radiator with a thermostat restricting flow to the rad until warmed up. If the thermostat is opening and the water pump is pumping and the hoses/rad are clear then I would suspect blockages in the coolant passages of the head/engine block etc.
 
As Grober 'waterless' coolant is basically neat glycol + snake oil logic and priced like as though it was pure gold, it's more viscous than a 50/50 mix of glycol and water and has a lower specific heat capacity.
Evans quote something like 0.66 BTU/lb.°F for their treacle while a 50/50 mix of the usual suspects is ~0.8, neat water is 1 and neat ethylene glycol is ~ 0.6
 
RBYCC said:
Don't forget something as simple as the coolant cap....

Also the aux fan circuit can be modified to turn on at a lower temp then the stock 105C.
My fans are modified to turn on at 92C. :thumb:
Click to expand...

Ed, this is something ive heard quite a bit over on the MB World forum.. how do you do it?

moonloops said:
If you have an air lock you can normally hear some gurgling going on if you move the heater controls from hot to cold and back again. My W202 had an airlock and it got very hot with no heat coming from any vents. Solution was to drop the existing coolant (needed doing anyway) and ensuring heater controls were set to hot refilled it, started engine and topped up as the fluid dropped..been perfect ever since.
Click to expand...

I dont know about a gurgling noise but there definately is some sort of rev fluctuation when I turn the fan from position 1 to full speed when on hot, is this the same?

Will said:
I'm pretty sure the early 300-24 engines have a bit of a reputation for liking a head gasket..

Heater matrix shouldn't affect running temperature or overheating.

Cooling systems on these cars are very, very basic. It's just a load of water/coolant pumped around a block and radiator with a thermostat restricting flow to the rad until warmed up. If the thermostat is opening and the water pump is pumping and the hoses/rad are clear then I would suspect blockages in the coolant passages of the head/engine block etc.
Click to expand...

Ive got the thermostat ordered so it should arrive soon...cant wait to try it.

I had the pleasure of driving Ian Walkers blue 300-24v coupe for a few weeks whilst he was installing the 3.2 engine in my saloon. His 300-24 was smooth as silk, sounded so beautiful and maintained temp perfectly! Thats my reference point for this engine.
 
Well.. this is how high it got today just sitting in traffic.. heaters on full.. engine to the point of almost shuddering when about to accelerate. Luckily traffic started moving so it came down to 100. The aux fans were definately on too.

9216908593_d6ac870e32.jpg
 
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Niks said:
I dont know about a gurgling noise but there definately is some sort of rev fluctuation when I turn the fan from position 1 to full speed when on hot, is this the same?
Click to expand...

Not engine revs (although electrical loads can briefly effect idle), typically gurgling noise sounds like air moving through central heating/water going down a partially blocked drain/someone is gargling mouthwash behind the centre vents in the dash

I take it the thermostat is yet to turn up or be fitted? You mention heater fully on... is it still not managing much more than 'luke warm' air?

FWIW the only time mine has gotten that hot is shortly before i replaced the waterpump and the aux fans would result in the needle dropping back to just over 100 and then climbing to about where yours is as they cycled. As soon as traffic started moving again it quickly dropped below 100 and slowly stabilised at 90ish.
If the heater is working properly it should be able to push out scaldingly hot air and fairly quickly lower the coolant temp a chunk... driving back from buying mine i got stuck in a monster stop/start traffic jam on the M1 and (wary of the rad top bleed being bodged with silicon!) used the heater in this way. Soooo unbearingly hot i soon decided i'd rather risk paying for recovery than get home with the car fine and end up medium rare myself. Thankfully the car took the third option and the silicon bodge held
 
Niks said:
Well.. this is how high it got today just sitting in traffic.. heaters on full.. engine to the point of almost shuddering when about to accelerate. Luckily traffic started moving so it came down to 100. The aux fans were definately on too.

9216908593_d6ac870e32.jpg
Click to expand...

Shame you were not able to pull over to check see if the viscous fan had cut in.
Should cut in at 96-104 degrees and you were at approx. 110 degrees.

However, you were not in anyway at a dangerous level.
 
Been mentioned a few times on previous posts, but I would start with the water pump, the impeller is probably spinning on the shaft, so you are getting some flow, but not fully, this would explain your symptoms with the heater. Would expect pump to be fairly reasonable and at least that element is then sorted. Had similar with a 300td and that was impeller. Someone had previously spent a lot of money changing rads and ended up being the pump in the end.
 
had similar prob with my w202 ,temp getting too close to the boil zone,changed thermostat and flushed the coolant, all was sweet after that ,replaced the viscous fan clutch for good measure.
so far so good
 
Update...

Took the car to Terry from Wayne Gates in Harrow who worked his magic and replaced the thermostat and checked the rest of the cooling system. We were pretty much 100% sure it was an air lock that was causing the problem between the coolant tank and the radiator. A bit of fettling around had the coolant recirculating through the system again.

The temp now maintains a constant 80/90 :)

Terrys a great guy, very knowledgeable and I would highly recommend him! :thumb:

Fingers crossed its now sorted.
 
Cheers nicks. Nice to meet you fella :thumb:
 
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