Cooling Fans - Mechanical vs electric

[Rob19]

Hello Folks,

 

This has turned into a somewhat lengthy update on progress with resolving the problem identified in my earlier post.

 

The first surprise on investigating the cooling system was that there is no thermostat. It seems clear therefore that this cooling problem is one of long standing and someone took it into their heads to remove an obvious obstruction to water circulation! Probably also the reason for the installation of the eFan.

 

I've changed the temp transmitter and installed the solid state voltage stabilser Andy recommended. Drained the system (seemed to be Bluecol's Inorganic Acid Technology) which was quite clean with little sludge and a good flow. I used Holts Speed Flush as a flushing agent, left it in for 15 mins at a fast idle, as instructed, then leaving it in took the wreck out for a bimble of about 40 mins duration achieving breakneck speeds circa 60mph.

 

During the bimble the indicated temp rose to within about 1/4" of the red section and stayed there pretty much all the time apart from one or two minor excursions to within 1/8" or so of the red section.

 

Drained the system which showed a reasonably clear flow from both the block and rad - certainly no rusty gunge - then flushed it with a hose including some back flushing of the block. The flow ran completely clear from block and rad, with good flow from both.

 

The novelty of working with a hose, outside in a bitter northeasterly had worn off so I packed up. A further flush is planned for next weekend, when I can get back to where the car is currently stored.

 

Observations:

 

Some apparent success in that the temp stayed out of the red when the car was under way and with the eFan not running. However the temp indicated still seems to be too high. Need to accurately measure the actual temp achieved though.

 

The two electric gauges still seemed to exhibit odd behaviour i.e. moving to lower values when the engine was idling and with a big drain on the battery due to the eFan running and there being limited output from the dynamo. Presume this could be because the voltage fed to the stabiliser in these circumstances could be less than the required output from it?

 

The heater was delivering air with the temperature of hot breath.

 

There still seems to be some sort of restriction in the cooling system which prevents adequate cooling.

 

What to do about the lack of thermostat? Invest in a bellows type?

 

Further thoughts would be welcomed.

 

Thanks to all,

 

Rob19

[jellison]

Electric obviously

[RogerH]

Hi Rob,

disconnect the heater pipes and see what sort of flow you get out of the engine to the heater using the engine pump.

Put a hose through the heater matrix and see what sort of flow you get through that.

 

Roger

[Edmond]

My TR4A ran very hot after an engine rebuild. Further draining and flushing the cooling system made no difference nor did an uprated water pump. I changed the temp sender; again nothing. What worked was spending £42 or so on an orginal type sleeved thermostat - immediately the temp guage registered bang on normal. It only rises when idling in traffic and I have adjusted the kenlowe to kick in a little above this. Happy as can be now, plus the dreadful 'run on' when I switched off has disappeared too. Hope you get sorted.

Edited March 8, 2011 by Edmond

[ianc]

Into the bypass hose, put a blanking plug with a very small hole. That will force the coolant to head for the radiator rather than taking the short cut.

Not a good idea to run without a thermostat - engines work best when they are running near the correct temperature and, especially in winter, if there's no thermostat, the engine will be below its design temperature for a long time (in fact, it may never get there).

Even in near zero ambient, my temperature gauge is almost up to normal running within 2 miles of my home. The oil, of course, is still cold, so I don't start to use higher revs (beyond 3,300) until I have covered about 8-10 miles.

Ian Cornish

[Geo_Hahn]

Into the bypass hose, put a blanking plug with a very small hole...

 

That is what I do (and much more) as I have to drive in 100F+ heat. I used a copper pipe cap (3/4") with a 3/16" hole:

 

[RogerH]

...I like that idea. It will go with the rest of the plumbing on my car.

 

Roger

[Rob19]

Thanks folks - some interesting suggestions. I fully understand the need for a 'stat so am interested in Edmond's experience. Being a bit of a traditionalist I like the idea of the bellows 'stat so will probably try that route. It'll be interesting to see if a previous owner's thinking that the answer was to remove the 'stat in fact made the problem worse.

 

Rgds,

 

Rob.