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[phil32]

Hi to you all...bit of a newbie here so please be gentle.

I had a nightmare journey when returning from weekend holiday towing a caravan. Had to get relayed by AA to home due to overheating issue.

Symptoms are sporadic-with wild temperature fluctuations seen at various times that don't match the situation.

At idle the car rises from cold to 92 degs at a steady rate holds briefly and then continues to rise to approx. 95 degs and holds. If revved to 3000rpm then temperature will increase to 100 degs at which point the radiator fan kicks in and brings the temp down to approx. 97degs- which I guess is all normal.
however
Once warm and driving, the temperature will rise again to 100 degs (fairly quickly) and the fan will cut in, this then occurs repeatedly (much worse when towing or in stop start traffic) -  the temperature does not then recover to any normal level until left to cool..
I have
 - recently changed coolant and levels are stable
 - water pump appears O.K as water is circulating through expansion bottle and inlet/outlet hoses are balanced when warm.
 - AA guy said temperature gauge at 100 degs but inlet/outlet hoses to rad at approx. 70 degs
 - head gasket O.K, no excessive pressurisation of expansion bottle if covered by hand

so ...Questions

car shows small amount of rust deposit on top hose leading from car heater heat exchanger to an inline unit (not sure of name) at the back of the engine bay - Is a small leak allowing air to get in and cause an intermittent airlock to build?
or
could it be a sticky thermostat 'at temperature' causing the fluctuations in temp sensor readings?
or
could it be something else?

Please help Thanks
Phil

[dbdb]

Have a look at the normal temps here http://www.omegaowners.com/forum/index.php?topic=90487.0

Towing might push it up I guess, is it only while towing?  100C is not normal but it won't boil at 100C, the antifreeze added pushes it to more like 105C but most of all the pressure makes it more like 130C, or higher. Has it just started doing this?

[phil32]

Hi, thanks for link.... confirms thoughts up to now,

It did start doing it before I did the coolant change. I've only had the car for 6 months so originally thought the coolant levels were wrong.

Is it possible the stat is trying to close after it has opened for the 1st time from cold?

[ronnyd]

Phil, is your car an auto?. If so you may need an oil cooler fitted. HTH.

[omega3000]

Mite be an idea to take the rad off and flush it through and reverse flush , i had similar problems but mine turned out to be a partially blocked rad 

[Andy B]

Phil, is your car an auto?. If so you may need an oil cooler fitted. HTH.

Auto's come from the factory with an ATF cooler .......... built into side of maim rad. 

My money is with EMD and Phil needs either a good flush through the rad, or more than likely a new one. I never had any overheating problems with my car till I started towing our caravan. A flush was only partially successful, but a new one sorted it ... even in the low 30s of mid France.   

[dbug]

Phil, is your car an auto?. If so you may need an oil cooler fitted. HTH.

Autobox oil cooler fitted as standard on these - incorporated into radiator.

Mite be an idea to take the rad off and flush it through and reverse flush , i had similar problems but mine turned out to be a partially blocked rad 

Go along with this - blocked, or partially blocked rad.  Had same symptoms on two Elites - new radiators cured completely

[sassanach]

stick you mitt on the rad,if you have cool spots then replace it,don't waste your time flushing,it will not work.refill with distilled water.

[phil32]

Hi to all,
Thanks for comments.

For reference - car is manual.

Update on driving is - car was fine today driving from Chelmsford to Witham (about 35 mins) temp stayed between 92 and 95 degs. Did go up to 97 once is standing traffic but then fan kicked in and returned to 95ish. Also cooler day today.

Have not found any cool spots on rad yet when running however will try flushing out the radiator properly tonight and advise on results.