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[Scatmancraig]

My 2.5 TD Omega has a slight cooling issue.

Up till now, it has been fine in normal driving. Temp gauge goes up to about 95, at which point the thermostat appears to kick in and it settles back down to approx 92, and stays there. The viscous fan kicks in at just over 90, which seems to low to me, but this is a separate issue.....

The problem is, when you drive the car a little more "enthusiastically", the temp gauge rises quite quickly to around 100. It may even go higher than that, but I didn't risk pushing the car any further. It comes back down fairly quickly afterwards, which is reassuring.

Last weekend I had a look under the bonnet. The radiator seemed to be fairly caked up externally with black gunge from a previous oil leak. So I removed it from the car and took it for a blast through a high pressure jet wash. I also ran a hose through it and made sure that there was no dirty water blocking things up internally.

The car still gets hot quickly when pushed. It's still perfectly fine under 'normal' driving. Both electric fans work as they should. It doesn't loose any coolant anywhere, so there clearly isn't a leak. I ran a hose through the rest of the system today to give it a decent flush out, so it's currently running on straight water. The water pump is pumping as I disconnected various hoses and left the engine running, and it was coming out at a fair rate. Got some anti-freeze waiting for me to collect tomorrow, so that'll be going in asap.

Any ideas why it might get so hot so quickly when pushed, but runs perfectly fine the rest of the time?  The last TD I owned also seemed to get hot when pushed, is it a characteristic of these engines?  I've no idea what normal running temp is on a TD, so I may not have an issue at all, but i'd be interested to hear others thoughts!

[Shackeng]

I found mine was the same until I gave the radiator a proper clean out. It now runs happily without the viscous fitted, & never gets above 95.

[Scatmancraig]

I found mine was the same until I gave the radiator a proper clean out. It now runs happily without the viscous fitted, & never gets above 95.

I might take mine off again and give it another go with the hosepipe.  It's a bit confusing as it has four hoses connected to it.  Two big ones that appear to be connected to the engine, and two smaller ones that seem to be attached to a small auxiliary electric pump mounted on the drivers side inner wing.  I've no idea of the best method of removing any internal crud.  No matter which way I connected the hosepipe to it earlier, all I got was clean water out. 

I took the viscous off mine last weekend.  It ran a little hot and even a normal journey got the electric fans on at low speed.  So I refitted the viscous.  Because I removed the bi-metallic strip thinking it was the same as a Senator (their viscous units are bolted from the front), I managed to bend the strip, now my viscous fan is on permanently!  No bad thing I suppose, apart from the excessive whooshing noises and detrimental effect on fuel consumption.

I'm collecting some anti-freeze tomorrow, it might help a bit.  Although I'm reluctant to put it in until I'm happy with the rest of the system.  I've got to do a transmission fluid change soon, so I'll probably remove the rad and blow the last of the old fluid out of the oil cooler part, then refit it all with the fresh anti-freeze in.  I've also got my eye on a new viscous coupling, so then I'll know if my old one was faulty as it used to come on at just above 90 degrees, which I always felt was too soon.

[TheBoy]

TD rads start to sludge up around 120k, esp with poor servicing.

Oilways, particularly the piston jets, sludge up with poor servicing.


Both can cause issues you've had, both *WILL* destroy head and/or HG if you hit 100C on gauge (110C in reality)

[Scatmancraig]

TD rads start to sludge up around 120k, esp with poor servicing.

Oilways, particularly the piston jets, sludge up with poor servicing.


Both can cause issues you've had, both *WILL* destroy head and/or HG if you hit 100C on gauge (110C in reality)

Well today I took it on a 40 mile journey to Cleethorpes.  25 degrees outside, and 4 people in the car.  There's a few long hills, 2nd or 3rd gear with foot hard down (auto box), and it peaked at 95 degrees on the gauge.  So it's not at critical just yet, and normal running it is fine, its only when driven hard when it gets hot.

Is it worth running some flushing oil through the engine before I change the oil next weekend?  I'd heard some horror stories about using it in engines as it can cause more problems than it solves.  The radiator is running nice and clean now, although it still has straight water in it and no anti-freeze at all.  Picked some up today so that'll be going in shortly after the oil change.  Is there any kind of cooling system flush product available, as I could run that through just to be totally sure.

[TheBoy]

Never run neat water in the coolant system, even this time of year, it will opps it.

If its history does suggest poor servicing (ie, longer intervals than the specified 4,500 mile oil change), put a very strong oil flush through it (not the type you leave in for a few miles, the sort you idle for 15mins).

Now you've shagged the coolant system as well, that probably needs a decent flush through - not the Holts shite Halfords sell.

[Scatmancraig]

Never run neat water in the coolant system, even this time of year, it will opps it.

If its history does suggest poor servicing (ie, longer intervals than the specified 4,500 mile oil change), put a very strong oil flush through it (not the type you leave in for a few miles, the sort you idle for 15mins).

Now you've shagged the coolant system as well, that probably needs a decent flush through - not the Holts shite Halfords sell.

Opps?  I'm not with you??

Any recommendations for a decent coolant flushing product?  Never used it before.  Do you add it in then drive the car for a while? 

The straight water has been in since yesterday afternoon, done approx. 80 miles since. I have 5 litres of GM red anti-freeze now, not sure what the cooling system capacity is on the TD nor what ratio of anti-freeze to water to add.

[Diamond Black Geezer]

For winter use 50-50, you can drop to 25-75 (or even less) for summer, but I run on 50-50 because it 'can't hurt' sort of thing. Also antifreeze has anti-corrosion properties, don't forget. From memory about ten litres in total went in, might be a bit under.   

[Scatmancraig]

For winter use 50-50, you can drop to 25-75 (or even less) for summer, but I run on 50-50 because it 'can't hurt' sort of thing. Also antifreeze has anti-corrosion properties, don't forget. From memory about ten litres in total went in, might be a bit under.   

Nice one.  I'm going to collect some coolant flushing product on my way home tonight and run it through the system.  Not sure what the procedure is, I guess it depends on which product I use.  I have a friendly motor factors that should be able to advise something suitable.  That anti-freeze you got me is 5 litres, so in theory I'll be pretty much using all of it, plus the same quantity of straight water to completely fill the system. 

Hopefully, this will improve things on the cooling front, if not I guess either my water pump is shagged or part of the system is badly blocked.  The water in the header tank is still clear, so I don't think there's a huge amount of crap still in there thats going to come out, but then I don't know how powerful the coolant flush is so I might be surprised.

[Shackeng]

Best to use filtered rain water if possible. Our water is heavily limed.

[Diamond Black Geezer]

Let us know how you get on with the coolant flush.. at present I've got my eye on my special product which is 79p/litre from Asda 

[Scatmancraig]

Let us know how you get on with the coolant flush.. at present I've got my eye on my special product which is 79p/litre from Asda 

Well, things are improving slightly.

Bought some coolant flush from my friendly local motor factors.  No time like the present, so I got home and cracked on.  Added the coolant flush, which conveniently says on the label that its better to use this in straight water, and left it running for the required amount of time.

Couldn't get enough of a grip on the drain plug in the radiator, so removed the small radiator hose that's next to it and dropped the contents of the radiator.  Flushed the system with more water, and tried to get as much out as I could be disconnecting various hoses and blowing through them. 

Mixed up some anti-freeze 50/50 and added it back in.  Had my tea, then went for a drive.  Viscous fan was howling away as usual, as it was when I arrived home a few hours earlier.  But as if by magic it stopped howling all by itself!  My return journey back home a couple of hours later was promising as well, as the viscous fan didn't cut in at all.  I thought that this must be a fluke, but the journey to work this morning was the same, normally the viscous fan used to kick in approx 3/4 of the way, I even deliberately went a very long way round and still no viscous fan.

Now all of this means that a) the viscous fan has decided to freewheel permanently, or b) the coolant flush and fresh anti-freeze has made enough of a difference to keep the engine cool enough to stop the viscous fan from reaching its locking point.  Confusingly, the temp gauge still reads exactly the same as it did before (sits at just over 90 normal running), and I haven't tried pushing the car harder yet to see if the gauge still gets hotter more quickly.  But I'd certainly say its a step in the right direction! 

[Diamond Black Geezer]

I've gone and asked a question you've already answered in another thread, re: the drain plug/hose - I'd say right choice pulling the hose off. So what was this wonder product? 

[Kevin Wood]

Temperature gauges often lie about what's really going on. Specifically, they have a dead point around normal operating temperature so the needle doesn't move too much with the normal fluctuations of temperature and panic the driver.

No experience of the TD's gauge, but bear that in mind.

Sounds like you've made an improvement. If the viscous fan gets annoying, bear in mind that many TD drivers report that it works perfectly well with just the electric fan. Store the viscous fan vertical if you do decide to remove it.

[Diamond Black Geezer]

Same with me, I reckon a new stat would help my engine, but there's nothing apparently wrong on the temp gauge... pinch of salt, really, I think. I does sound like Mr Scatman has done good.