Overheating - strange?

[KellyJones]

A slight problem with my little project (850 cd t5 1996)
Head gasket just done and it overheat after being on idle for around 15mins, odd part is the temp gauge reads halfway and no fans cut in, top and bottom hoses are hot and i dont seem to have air locks etc.........is there a temp sender that could be faulty?

[daveforber]

When you say overheat but no fans and normal temp gauge ... what exactly are the symptoms? Steam escaping?

[Dangerous Dave]

Theres only one temp sender and that is to the left of the inlet manifold. I've replaced mine twice on my car now, they can be a right pain.

Could be the fan relays are playing up, they are located on top of the radiator, and check the fuses to the, could be that one has blown?

[KellyJones]

.........it biols up from the expansion bottle,

[t5 pete]

Are the top or bottom hose's hard when hot also did you replace the thermostat
If the fan is not kicking in i would deffinatly look at the temp sensor and relays also cheack the wiring as ive hear of problems with the wireing breaking up leading to the relays

[KellyJones]

Hi Pete, I did change the thermostat, hoses seemed soft and hot! i think on the basis the temp gauge was only ready half way it firstly point torwards the temp sender, any ideas on best place to get one form and how much they normaly are? where is the unit located? thanks for your help.

[jez.w]

Sounds like the head may still have a problem to me?

[KellyJones]

Sounds like the head may still have a problem to me?

Hi, the head was mint, i had the head skimmed and pressure tested, all was good, could i have missed somthing else with the head? the fan did not cut in hence me poniting torwards the temp sender, thanks for the response.......

[Jamest5r]

Hi mate, had the exact same thing when i swopped my engine, for no reason what so ever the fan would not kick in, tested the fan by jumping and it worked so just run a direct feed to the battery, all sorted.

Do this before you spend money on sensor's like i did.

[tylerman]

I looked at this car when it was for sale and the owner said that it was definitely head gasket although I reckon it could be the rad mixing water and oil together as it is a common fault?
Unfortunately the owner had started taking the head off so couldn't check.

Something to bear in mind, fingers crossed you get it all sorted :-)

[KellyJones]

hi, correct he had started taking bits off it, when i took the head of the gasket was perfect! never minfd i bought it as a project ......o what fun! cheers

[Dangerous Dave]

Have you checked the expansion tank cap is ok? also the tank can develop cracks around the base of the neck which eventually leak, so thats another thing to check. A new tank from Rufe is not much.

[KellyJones]

Thans for the responses so far, very helpful as ever! so back to the temp sender, anyone have a diagrams showing its location, and the best place to purchase one from? cost? cheers, Peter

[T5frankie]

could just be a faulty cap i've had one before

[Dangerous Dave]

The temp sensor is located underneath the top radiator hose in the thermostat housing. Its a bit difficult to get to unless you undothe top hose.
http://i150.photobucket.com/albums/s101/bomb192uk/bay.jpg

I had a sensor from eurocarparts but it broke after a couple of months, the other I got was from Partsforvolvos, genuine Volvo is the other option from Rufe. The exact same sensor is also found on some Renaults.

http://www.partsforvolvosonline.com/product_info.php?cPath=608_664&products_id=3867

HTH

[KellyJones]

Will get a cap also, best place to get one?

[streaky744]

blocked heater matrix causing air lock?

blocked radiator or water pump worn out so not pumping enough water round at correct rate?

my bet would be simply a stuck thermostat or sticking one. take stat out and try without it in see if problem persists (cost nothing to try but time) if cures it fit new stat

and worse case have the sniff test done on it see if gas's are mixing and if so it could be bottom end thats the problem, cracked liner maybe?