Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[Evo]

Hi folks, my manual 1996 25DT has done 174,000 miles and recently started to have a higher water temp which increased with hills & high speed (91 to 94) whereas before is used to be at about 85. I thought better to investigate before it gets worse.


So I got a new 80C thermostat from Euro Carparts & tested old & new in a pan of hot water. This showed that the old one was tending not to close as the temp reduced! This explains why the heater was always poor but not my new temp variations.

Put it all back together using the old sealing ring as the Euro Carparts supplied one was incorrect. On driving found I had the same temp variations but also a coolant leak.

So stripped it down & this time I thought I would take the water pump out. Small bit of play in the bearing but the plastic impellor was intact.

I have a newish drive belt with a recent replacement of the tensioner .... so my only conclusion is that the radiator is past it (though I did try back flushing it with a garden hose & it seemed fine). Are there any other explanations I've missed? Engine is fine & idles very steady.

Any suggestions please as to where to go for a replacement rad? My car has air con. How much would a dealer one set me back?

Incidently I can't work out the purpose of the two small bore rubber hoses on the rad that go to a fitting next to the fuel filter. These are addition to the two 2" main radiator hoses on the radiator. Can someone enlighten me?

By the way I wasn't able to undo the 32mm fan nut without buying a Sealey VS095 viscous fan holding tool (£10) to use with my Campag bike spanner.

[same #same#]

could it just be the temp sensor at fault.

[charlie]

so youve put in new stat,then the car runs abit hotter,With the old one not shutting as it should,may be before your was running cool rather than running hot now.

[osealy]

I had the same problem! I changed the pump & stat, no difference! Had to get a new rad 180 Euro for auto + aircon , problem fixed. Mine tended to head for 100c on inclines in summer.

[hoofing it]

if your running with the viscous off the temp will sit around 85-90ish, mind you need to keep air-con on as the electric fans take over from viscous and don't tow anything with fan removed
as for the rad the pipes your on about are for the autobox oil cooler

[TheBoy]

How often do you change the oil?

[supradino]

i've had the same problem heading into the 100's changed water pump and removed therm and still doing it, have got a second hand rad on the way, is there a guide to removing the rad on a 2.5td anywhere??

[Evo]

Thanks everyone for the replies. Much appreciated.

How often do I change the oil?  I change it every 5k & have done from new.

Well I stripped it down again & put a new thermostat gasket in, replaced the waterpump (old one was leaking after I'd tried to take it out) & also fitted a Nissens rad. Had to use a blowtorch (gently) to get the water pump pulley off.

Someone asked about how to replace the rad ... I found it fairly straightforward. Still don't know what the function of the two smaller bore hoses are. My gearbox is manual & the hoses terminate in a small Bosch module (next to the fuel filter) which has an electrical connection. Hardest part was removing the factory fitted hose clips.

End result ... still got variation in the temperature .. so perhaps it is the temperature guage sensor ... as someone suggested. I'm starting to lose the motivation to do anything further..... can anyone tell me where the sensor is please? I guess it's all good exercise ... 

[charlie]

underneath in intake manifold,theres two one for the temp gauge and one for the ecu,i believe the one for gauge is a single wire one,

[irpearce]

I'm facing exactly the same problem. I have:-
Fitted new waterpump (old one was OK anyway)
Removed thermostat completely for max flow
Removed and flushed Rad with acid cleaner - flow defiately improved but how good does it need to be?
New drive belt
Used K seal in case there is a head gasket or crack problem
It does not lose coolant which is clean.
No water in the oil
My TD has done 230k and until recently always ran at 90 degrees - now it heads over 100 as soon as I look at a hill
What next - loathe to buy a new rad which costs twice the value of the car! and it might not work
Any more tests I can do?

[hoofing it]

I'm facing exactly the same problem. I have:-
Fitted new waterpump (old one was OK anyway)
Removed thermostat completely for max flow
Removed and flushed Rad with acid cleaner - flow defiately improved but how good does it need to be?
New drive belt
Used K seal in case there is a head gasket or crack problem
It does not lose coolant which is clean.
No water in the oil
My TD has done 230k and until recently always ran at 90 degrees - now it heads over 100 as soon as I look at a hill
What next - loathe to buy a new rad which costs twice the value of the car! and it might not work
Any more tests I can do?

replace rad with a copper brass one.I got a old rad from scrappy and had a copper brass insert fitted touches 90 at a push now + no viscous fitted

[hoofing it]

Thanks everyone for the replies. Much appreciated.

How often do I change the oil?  I change it every 5k & have done from new.

Well I stripped it down again & put a new thermostat gasket in, replaced the waterpump (old one was leaking after I'd tried to take it out) & also fitted a Nissens rad. Had to use a blowtorch (gently) to get the water pump pulley off.

Someone asked about how to replace the rad ... I found it fairly straightforward. Still don't know what the function of the two smaller bore hoses are. My gearbox is manual & the hoses terminate in a small Bosch module (next to the fuel filter) which has an electrical connection. Hardest part was removing the factory fitted hose clips.

End result ... still got variation in the temperature .. so perhaps it is the temperature guage sensor ... as someone suggested. I'm starting to lose the motivation to do anything further..... can anyone tell me where the sensor is please? I guess it's all good exercise ... 

Every 3k MAX

[Evo]

irpearce please take note. I decided to measure the engine temp to sort out if it was the temp gauge in error or the engine getting too hot. I thought about buying an IR thermometer but instead used my Fluke digital meter with an accuracy of +-1C.

For a temp gauge showing 91C the highest I could measure with the thermocouple taped to the engine block was 74c. This was with a new 80C thermostat. This was the sort of reading I always used to have in the past.

So the conclusion is it's the temp guage in error. To replace the temp sensor would cost about £25 & mean taking the inlet manifold off I beleive. So I'm inclined not to bother. I'm now reassured that I can take the car on the continent in the height of summer without overheating problems.

Thanks for the advice about changing the oil every 3k. What makes you think it's nessecary? I notice that the same engine (M51) in a BMW has a oil change interval of 10k I beleive. Vauxhall recommend 5k & oils have improved since the car came out.

They now say 10k for a 10W-40 A3/B3 oil in a pre 2001 car
http://www.vauxhall.co.uk/vaux/owners/servicing/servicing.do?method=view

I once phoned an oil company help line about whether changing the oil earlier was worthwhile. The advice was to put the money saved by sticking to the manufacturer's spec to buy a better quality oil.

But there again a replacement turbo is not cheap.

[arth]

Well 3 year ago in summer, my Omega, reached easily this temperature   



This temperature was reached in summer, with outside temperature is 40-45ºC on the highways going at 140 km/h reached 100º and once inside traffic went up to that level

Firts step was cleaning all water system, during the process, we definetely had to change the radiator, after all the temperature decreased, 90º on highways and 100º in city traffic.

Since then situation for me is same although the water pump was changed in 2008 the car still keeps that temperature, so I face a big problem in summer, as in higway I cannot go faster than 140 km/h otherwise the car will heat again.

In Spain the heating of OMEGA is a well known problem, hence here temperatures are much higher than in UK  8-)

There is a thread in this forum about this:

http://www.forocoches.com/foro/showthread.php?t=251677

They said that OPEL has made some modification in front spoilies to avoid this, but in my city the official service does not have any internal communication about this

Solution should b something like this





I still have the problem so in summer I have to be quite precoucious with the temperature

Antonio

[Omegatoy]

Hola Antonio!!
I to live in espana, my omega never gets above 95, i change the oil every 3k(miles) 6000kilometers, as this engine uses oil for cooling the engine via jets in the conrods/crankshaft area,
when the oil is not changed enough these block up and the engine runs hot!!! if you have access to a engine flush additive then use it and change the oil a few times in a short time this usually cures it if the flush is strong enough?
hope this helps?