Electric Fan

[prvtsmallparts]

My 1850 HL is overheating and is in the garage for some checks, when it gets out I want to get an electric fan to help out  in town. My commute includes a 20minute queue and want to do all I can to keep her cool.

First... good idea or not, if so can anyone suggest the besy fan to get

[32valves]

Quite simply your car should not be overheating if everything is in good condition. Fitting an electric fan could just be masking a more basic problem. What do you mean by overheating ? Does the temp guage go of fthe scale and is water being forced out of the overflow pipe or does the guage just settle a little on the high side ? It could be something as daft at the voltage stabiliser.

[prvtsmallparts]

Well it starts all ok and then within 5 minutes is on 75% then it will stick there or go slightly higher dependigng on whether I'm in traffic or open road. Then after about another 5 minutes the heater finally starts pumping out hot air and the temp stabilizes, back to half for 5 minutes.
Then it fluctuates wildly between half and 80% whether I am in traffic or not. I use the car every day and have used a pint of coolent per week per week.

There are no obvious leaks. This why its in for a good service. What I was thinking was that perhaps when the problem is finally solved an electric fan might help to keep her cool in long traffic queues

[32valves]

Get the system flushed out and replace the thermostat. Is the radiator in good condition too ? Is the fuel gauge behaving itself ? This is connceted to the voltage stabiliser also and could indicate that this is the problem. Clean the connection to the temperature sender. If all the above is OK and the temperature guage is still fluctuating while driving, then suspect the head gasket. Try a compression test.

[AdamSindrey]

My heaters start blowing out hot (warm) air after about 2 minutes.    Air lock?

[Eddy]

As an experiment, completely remove thermostat.
The engine will take longer to warm up (only a problem on cold January mornings).
Sometimes, thermostats are more trouble than they are worth.

Eddie

[trackerjack]

I think removing the thermostat is not a good idea as if the engine runs too cool the wear rate goes up and the fuel consumption will be dreadful.
I was told the slant fours actually need to be very warm for efficency.
My car has a thermostat and still manages when thrashed on track days.

[32valves]

Do not, under any circumstances remove the thermostat. Your engine will DEFINITELY overheat in traffic if you do. Without the thermstat, water is pushed through the radiator too quickly to be cooled effectively at low speeds or idling (if you don't believe me, try it !). There's no two ways about it, forget all the scare stories about Dolomite cooling systems. If everything is in good condition, it's more than adequate. My Sprint, with its completely standard cooling system (no electric fans, fancy radiators, bypass pipes etc) survived a thrash up the Stelvio with no problems at all (and we'd been driving more or less continuously all day to get there). I'd be happy to take a look at it if you're not too far away.

[Mad Mart]

Quote:

Do not, under any circumstances remove the thermostat.

Absolutely correct. The thermostat on a Sprint/1850 has a foot on it which, when open, closes off the flow of water around the engine block & diverts it through the radiator.

[AdamSindrey]

Does it?  Do you mean aswell as around the block it pumps it through the rad? 

[Mad Mart]

You've got it Adam!

[Eddy]

The role of the thermostat is to heat the engine up quicker, by preventing the coolant flowing through the radiator when the engine is cold.
As the engine warms up, the thermostat opens, so enabling the coolant to flow thro the radiator.
The worse case senario is when the thermostat fails to open, or doesnt open sufficiently. The radiator is the only means to cool the heat in the coolant. Any restriction of the cooilng flow to the radiator when the engine is up to temperature is very bad news.
You do no harm in removing a thermostat; potentially a lot of harm in retaining a faulty one.
Ive run a car without a thermostat for a long time, the only problem is on cold January mornings as the heater takes longer to work.

[trackerjack]

Thermostats cost a couple of quid or peanuts.
My son had an Escort LX with a stuck open one result poor heater and 24 mpg as opposed to 35 mpg
Say 10 gallons at 11 mpg = 110 miles extra or at 35 mpg waste 4 gallons cost is £16, result no thermo = no brainer.

If you have to run with no thermo it shows there must be a fault.

The other result is as your engine WILL run too cool hence too rich on fuel the bores will wear out much faster.

Why no thermo Eddy?

[bodgerben]

As a few people have already said, on the slant 4 engines there is a bypass tube from the water pump cover to the inlet manifold. When the stat is closed the bypass is open - the pump cannot push water out of the top hose (the stat is closed) only via the bypass. Normally slant 4's warm up very quickly, with a lovely toasty heater partly due to this nifty bypass.

If you remove the stat the water pump can now circulate water out of the top hose, and via the bypass - the water that goes via the bypass has not gone through the rad.

If you run a EWP the bypass needs to be blocked either with core plugs (no bypass tube) or a special bypass tube that has no hole.

In short, don't run a slant 4 (or Stag with a bypass tube) without a stat.

prvtsmallparts - slant 4's normally have great heaters, pumping out hot air after only a few miles. With the heater valve open are both heater in - out pipes getting very hot? I don't think you have a problem with the pump, (the skew gears get worn, and the pump does not turn, but the car will quickly boil, and you'll have cold hoses, no circulation). Finally how old is the rad?

I use an uprated rad for my road 1850 (with only a leccy fan) this is mainly due to the short trips I do, and in winter I did not want the fixed 1850 fan being used.

My track day Sprint has an alloy rad which is great, but I did use the nomal uprated rad with no problems on lots of track days and sitting in traffic with no problems - the original rad was causing me problems after being thrashed and waiting in the paddock for the next thrashing.

Both these cars use leccy fans, but for different reasons - remove the fixed 1850 fan for winter short trips, and one for ease of control in hot conditions. But both these have great heaters. If the rest of the cooling system is up to scratch a leccy fan can help for greater control - I use kennylows, with thermostatic control from an alloy hose adaptor I got from demontweaks (not the kennylow in hose gubbins).

I'd check the heater, if both hoses get good and hot before the stat opens I'd then check the stat itself. And I'd also check that the rad is in good condition and gets hot all over (no cold spots). Finally I would ditch the 1850 fan and put a kennylow on there. The Sprint fan is better as in good condition it should only turn up to a few thousand revs, not fixed like the 1850's.

[Eddy]

I originally suggested to remove the theromstat AS AN EXPERIMENT.
The thermostat represents a flow restriction to the radiator, particularly if there is a partially blocked radiator and/or something else. The experiment could determine if this was/wasnt the case.
I dont advocate running long term without a thermostat as a first choice.
Yes, Id love and prefer all cars to run perfect all the time, as they were driven out of the showroom.
Thats not practical for me and a lot of others, im afraid.