What Temperature is to high?

[kaiser]

Originally Posted by SD1too

Remember what you were saying Kaiser about we British learning to speak our own language? Well, in the context of your posting it's a wheelarch. In English a fender is a cushioning device hung over a ship's side to protect it against impact.

Simon

Ha ha Simon.
When you speak more than one language, you will occasionally also let a stranger loose.

But fender is quite appropriate in this case. Viking ship, cushioning against impact. See? Sea!

Further, your own language is actually Danish, Norwegian and Swedish, mixed up with whatever your ancestors were speaking before my ancestors came and taught you the fear of Thor and Odin.!

I couldn't get myself to point that out the other day, but now you have asked for it.

[kaiser]

http://jalopnik.com/5964599/the-best...os-of-all-time

for all the infidels!

[Oli_BN1]

Originally Posted by T-Cut

The 1.8 fan will run at high speed if the coolant reaches 112C. It will also do this after stopping the hot engine if heat soak raises the head to 112C. It will run on for several minutes. All this is independent of the slow speed resistor.

The simplest way to check for resistor failure is of course the universal Demist button.

TC

Ok my air con is working fine, demist no problem, and I can get hot air almost straight away after starting the engine. I'm not leeking coolant from anywhere and I've just had new piping and radiator fitted.

The fan comes on after long drives/ being stuck in slow traffic, and it stays on for a few minutes after cutting the engine.

The garage I took it too seems to think I need a whole new fan.

If the fan is only running on high speed, does this mean I'm likely to overheat the engine/ cause HGF?

[SD1too]

Originally Posted by Oli_BN1

The fan ... stays on for a few minutes after cutting the engine.

That's the fast speed running which suggests that your engine is running too hot because the slow speed has failed.

Start the engine from cold and press the 'demist' button. Now walk to the front of the car and listen at the radiator grille. Can you hear the fan running? If you can't, your slow speed has failed. Please report back and we'll tell you what to do to save some money.

Simon

[T-Cut]

Originally Posted by Oli_BN1

OK my air con is working fine, demist no problem, - - - If the fan is only running on high speed, - - -

You can't have it both ways I'm afraid.

TC

[RobPlews]

Hi all,

Interesting reading this thread.

I’m after some opinions re. an 82C PRT from DMGRS.

I was running an original buff one which I believe was 92C. Cruising along on the flat the temperature was always in the low 90s. Going up hills will see an initial rise but things soon even out. Stopped for a long period in traffic it would rise up steadily until the slow fan kicked in at about 104 then fall quickly and start all over again. Lovely - just as it should be.

While I was doing a recent belt and water pump change I swapped to an 82C from DMGRS - just seemed a good idea to take the load off the old girl a bit. But it’s behaving oddly.

Warms up nice and steadily but cruising on the flat is seeing temperatures in the mid 90s. Odd for an 82C stat I thought... climbing long hills (I’m in the Pennines so plenty) sees the temp rise to about 102-103. Ive just taken it over the highest pass in England at about -2C and it did just that and when I stopped at the top and opened the bonnet the radiator was clay cold and only just starting to get warm on the inlet side by the time I’d got out and opened the bonnet. The temperature does not continue to rise once stopped - it falls back to the mid 90s WITHOUT the fan coming on and the radiator gets warm and it will sit and tick over in the mid 90s forever without ever bothering the fan. The radiator gets hot at the top so there’s some flow and it’s ultimately cooling the engine but at too high a temperature.

Am I missing something here? Clearly there is a good flow round the block via the PRT (heater is good and I’ve driven it up to 35 miles with no problems). Radiator can’t be airlocked as there’s enough flow to keep things in hand when standing still and even up the steepest of hills. It’s just all just happening a bit high up!

I’m not loosing any water, there doesn’t seem to be any pressure where it shouldn’t be.

Over Christmas I’ve put the original back in and it was grand - just as it always was. I thought perhaps I had a small leak so was loosing pressure but it runs cooler with the hotter stat! Once I’d checked that I put the 82C back in and it’s all wrong again.

All I can think is this new stat isn’t opening at the correct temperature hence the water isn’t circulating round the radiator until over 100C.

Cheers

[kaiser]

I would take the radiator and disconnect both in and outlet. Then flush back and forth with water and maybe add compressed air.
I have recently done that to my one MGF (same engine, in essence) and I got out about two spoonful of "gravel" or rather rust the size of coarse sand.
There is plenty of that in mine! These particles are big enough to block many of the cooling channels, and I guess you could be running at about 50% of capacity, if not less!
I will do this next to my daughters 1,8T, which also seems to be running hot,
I did it earlier to my other F, except I farmed the job out, so I did not see what was in the radiator, but in retrospect, that car ran much cooler as well.
Try it and let us know. I think it might well be your problem!

[SD1too]

Hi Rob,

Thanks for a very clear account. Your new 'stat cannot be 82 degrees. In minus 2 degrees ambient your engine would be running very cool indeed.

Your original buff 'stat sounds to me to be the ideal spec: 88 degrees. Stick with that one.

Simon

[T-Cut]

Originally Posted by RobPlews

Over Christmas I’ve put the original back in and it was grand - just as it always was. I thought perhaps I had a small leak so was loosing pressure but it runs cooler with the hotter stat! Once I’d checked that I put the 82C back in and it’s all wrong again.

The logical conclusion is your new 82C PRT isn't opening at the secified temperature. The OEM buff version was 88C, so typically provides 90-100C driving year round. Why not try testing the new stat in a pan of hot water and see if it actually starts opens at the expected temperature. It will presumably be open when the water boils according to your report. I'm sure DMGRS will exchange it if it's wrong.


TC

[kaiser]

The temperature of the stat is irrelevant, if the heater and cold air in the engine department does the cooling. In cold weather it is entirely possible to cool to under 88 degrees, just using a heater on full blast, especially on fast runs with little engine power being used and lot of ram air. You can actually see this clearly, if you coast down a long incline and use a gauge that shows what is going on directly.
So on cold days, the main radiator is sometimes hardly even used. The coolant circulates in the block and the heater, and never reaches the temperature required to open the thermostat and involve the radiator!.

I remember a long trip in my V6 an early winter morning with minus degrees, there was some heat in the heater, but not a lot, and I stopped and checked the radiator. Stone cold! From memory it was about 5 or 7 degrees under 0!
In our 1.8T, in winter, it was common to see the temperature gauge under normal, on winter runs on the highway. You would only get the temperature fully up, if you kept the heater off, until the temperature rose.