overheating

[G-man]

Ok guys on behalf of my friend...

""my engine hits over 100 degreese, we have new radiator in it, oil is fine, water levels are fine... its fuel injected... what else could be wrong with it?""

Its not a mopar this is a general mechanics question. Basically his car drives n then goes to red line in tempreature... the oil in the motor is topped where it should be, brand new radiator... what else could cause over-heating issues?

[carolina charger]

 I assume the 100 degrees is celcius- check water pump, electric fan, thermostat, if none of above, check head gasket, head.

[suntech]

Blown head gasket??  Is there any pressure in the cooling system?? Thermostat that is not opening properly? Thermoswitch for fan that does not kick in??
What kind of car is it?

[tan top]

brand new rad Eh    air locks in the system

why was the new radiator fitted   leaking & run out of water was it ok before ??

[G-man]

citroen xsara 99 model

Radiator was dmged and was not fitted propperly.

He doesnt know if its blown head gasket.

the Temp sits just below red... sometimes goes over...

New radiator, fan does work... kicks in when the temp hits 100-110 deg C

He asked "how do you check for blown head gasket"

[lisiecki1]

first check for coolant in oil (milky white substance) or oil in coolant, if neither of those is an issue then an easy way is to leave the radiator cap off and run the engine to operating temp and if it starts blowing coolant out of the radiator you probably have a blown gasket....however, if the thermostat is bad it will make the car over heat because it wont open until enough steam pressure builds up in the head to physically blow through the thermostat, it will look similar to a blown head gasket, but subtly different as it comes and goes with the opening/closing of the thermostat....the pressures produced in this situation can destroy a new radiator.  If it's actually a blown head gasket, once the thermostat opens it will constantly blow coolant out of the radiator.  If time and money are an option you can buy a chemical head gasket checker from a number of tool companies (mine was from blue point-which is a division of snap-on).

[Ghoste]

It wouldn't hurt to shoot it with an infrared too and just verify the guage.

[G-man]

Radiator coolant blows out on/off

Thermostat?

How do you replace that... and what is a thermostat 

[Ghoste]

Replacement procedure varies depending on where it's located on the car and for a Citroen I don't know.  That said, it is usually located on the engine at the base of the rad hose which is returning coolant to the radiator. 
It's function is to hold coolant in the engine block until the engine is properly warmed up.

[Cooter]

Hold up guys how do we know it's actually running that hot??
We're assuming that the gauge is correct...

[Ghoste]

That's why I said to shoot it with the infrared. 

[G-man]

He said gauge is fine and the mechanics tested thermostat and it is fine...

Is 100 degreese-110 celcius fine?

Gauge has been tested to...

stuff if i know

[lisiecki1]

100 degrees celsius is in my worried zone....110 would bother me...A LOT....I would think it should be closer to 85.

What's the current outside temperatures like in your area?  Also, has the radiator been losing coolant and needing to be topped off regularly?

[Cooter]

If you aren't running an overflow (Puke tank) then it will blow out a certain amount of coolant and there's NO replacement to go back unless YOU do it...

[resq302]

How is the timing on the car?  I had a problem where my carb was running too lean and it was causing a hot condition.

[Cooter]

On MOST newer cars today, the Electric cooling fans will NOT come on till 227 DEGREES F.

This may seem a little hig for an early vehicle, but normal on a late model...