# Peugeot Boxer 1999 Petrol Engine running hot



## Chrissie Ferngrove (4 mo ago)

I've had Cymbeline (my Symbol Autosleeper) for just over 5 years now and a problem has developed this summer in the hot weather. The engine temperature goes up to about 110 degrees on the gauge and although the engine seems to be running ok, if I turn it off for a stop, I have problems getting it started again. I have taken it to my local garage and they have fitted new coolant temperature sensors and done a full service, but they couldn't find the cause of the problem. They also fitted a manual fan switch as the existing one had broken, so now I can control the fan manually and, to be honest, I need to have the fan running all the time and still the temperature is too hot.

A friend suggested that perhaps Cymbeline didn't like the new E10 petrol, so I have now filled it up with E5 instead, but it's still running far too hot. The temperature gauge isn't going into the red, but it stops just before it does. It's a bit worrying and I'm not sure what to do. Has anyone else had a similar problem?

Thanks for any advice.


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## Relyat (Oct 6, 2020)

First step would be to flush the cooling system using one of the propriety products. At the same time clean the outside of the radiator, checking for broken and bent fins and any obstructions. Depending on access replace the thermostat at the same time. 
Then refill and see if that helps.


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## Pat-H (Oct 30, 2009)

Its unlikely the engine is producing too much heat. A leaking head gasket could be forcing combustion gases into the cooling water but that would cause you to boil over repeatedly.

So its likely to be an issue with the cooling system. You know the temperature sensor is ok (as they replaced it).
It could be a stuck thermostat that is restricting the water flow. By the time you remove it to test it you may as well replace it (get a new gasket for the housing as well)
It could be muck in the radiator limiting the flow. Running with a flushing fluid and then draining and refilling may help as suggested.
Also making sure the external rad fins are clear and not blocked is a good shout.
Does turning the internal heater on Hot and the internal blower on high help reduce the temperature reading? (you are using a extra small radiator so its a useful test)


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## Relyat (Oct 6, 2020)

?


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## weldted (May 1, 2005)

If you are going to try flushing the rad. Remove the thermostat first it will give a better flow around the system. You can also see if it was the thermostat by rinse out the flushing content fill with clean water and see if it runs cooler. When the engine is up to temp, carefully remove the rad filler cap fill till it overflows then look for small bubbles in the filler opening if you get a steady stream it could point to a head gasket leak. They are known for it especially if allowed to boil.


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