car overheating whilst towing

[Thelma65]

Hi just thought i would ask the question just incase anyone has knowledge?

recently whilst towing to france - my car started to overheat whilst climbing some large hills
and then when stuck in traffice on m4 did the same
apart from the obviuos water top up - would there be any other reason why this might be happening

i drive all week and do abt 1000 miles and dont have this problem when not towing?
any suggestions?

 

[ChrisUK]

What car / age, what weight caravan; have you towed with it before and its not overheated?

 

[SirRogerFFS]

Hi Chris .
My first thoughts would be is the headgasket sus and then maybe it could be your thermostat sticking Does the vehicle over heat to the point your heater blows cold air. so manythingshere obviously headgasket being the worst case.
Next ,,,,,,,, has your heater sytem got an air lock anywhere.
Just a few things there to have a look at,of course you could have a split hose somewhere.
I wish you luck
Sir Roger.

 

[Thelma65]

thanks guys
i have towed loads with this car - peugot 407 sw - stirling emarald set up
air lock sounds interesting as - my blowers dont seem as powerful and my aircon doesnt feed through like it used too

 

[DomDom]

All the symptoms are consistent with a failed electric fan. Either the motor itself or the thermo-switch which operates it. This would explain the poor air-con performance, the overheating in traffic when there's no airflow and the overheaqting when under extra load, i.e. towing. That'd be the place I would start.
Dom.

 

[stevecritchlow]

I had something similar with a Citreon Xantia. Would overheat under heavy load, but would cool again when moving well. I thought the fan was ok, but it was a twin fan (pair of fans) and the second one wasn't cutting in when required. The fact one ran made me think the fans were working, but on heavy load both fans were required. When driving solo and moving freely a single fan and the air movement through the rad was enough to control the temperature

 

[Steve L]

I concur with Dom.
It could be the thermal switch mounted in your radiator. I would change the thermostat too as it may well of not been changed for a while and they do distort causing a higher engine heat temp prior to operating. Unless you have either bubbles /froth in your coolant expansion tank or a grey smokey exhaust or white emussion in the oil filler/dipstick, it is unlikely to be a head gasket.

First check to do is leave the car running until the temperature guage goes well up to the red. By this time the electric fan should of kicked in. To check the fan. Disconnect the plug on the radiator thermal switch. There should be only two wires to the plug. Using a paper clip connect the two sockets in the plug for the wires. Get someone just to turn the ignition on only. This should activate the fan. Thus confirming the switch malfunction.

On a Renault 25 I had for towing, I connected two extra wires to the thermo switch and terminated those near the top of the engine bay with a female spade connector to each wire. Then i used a standard 10amp car fuse fitted to the connectors to by-pass the switch when towing. A bit "bodge it and scaper" but it worked a treat.

 

[kenf]

i'm not a mechanic (i have a garage but its nearly all body work) but the peugeots were famous for blowing the head gaskets a while back (309/405/406) and it was found to be the radiators that were to blame all along , they were blocking up , no amout of flushing worked, i had a 309 that blew the head gasket , changed the gasket and still she kept heating after a while,after i heard this about the radiators i dismissed it as i had flushed the rad but i thought for the cost of a new rad i would try it !! it was a completly different car !! the hand droped a quarter of the clock , i'm not saying this will cure you though !!!