Electric Fan Question

[poolboy]

A 12 inch fan doesn't move much air..that's a fact.

 

[martx-5]

A 12 inch fan doesn't move much air..that's a fact.

It all depends on the fan that you get. Many 12" fans only move about 800 cfm. The one I'm using moves 1630 cfm.

 

[Jim_Stevens]

My 3a had the same problem, but here in Virginia. I have 86-mm pistons, though. Fixed it with an aluminum radiator and electric fan. Cleaning just didn;t work for me. Jim

 

[djwoody]

My gauge also climbs very close to the red zone in heavy traffic on hot days. Here in Toronto we have had temperatures in the low 90's several time this summer. Add to that high humidity and I find myself driving with one eye on the road and the other on the temp gauge. It's exactly what you describe - start moving and after a couple of minutes the temp drops to a "comfortable" level but hit traffic again and it instantly climbs back up again.

My radiator was re-cored about 3 years ago and I did a complete flush & fill before storing the car last winter. I have an electric fan (in front - pushing air) but it doesn't seem to do much either - I think it's a 12" unit but only kicks in when the temp gets very high. I can't turn on the heater because my blower motor is not functioning.

I've taken to driving around with a gallon jug of water in my trunk just in case but wish I could find a way to get that fan to be more effective. Maybe it's just an inaccurate temp gauge??? I've also wondered if replacing the thermostat might help.

 

[TFB]

Dion,what happens when fan comes on?If motor temp drops you may be able to just improve fan control with different(lower) range sensor,adjustable control,or manual overide.
Also,what do you do with the jug of water,pour it on the radiator?
Have fun Tom

 

[TR3driver]

One simple test for temp gauge accuracy (and whether the thermostat is working) is to start the engine and let it run at a fast idle with the hood up. Feel the top of the radiator from time to time as the gauge starts to climb. It should stay relatively cool until the moment the thermostat opens. When it suddenly gets hot, the temp gauge reading should match the thermostat rating.

My TR3A worked very well with just an 800 cfm 12" electric puller fan and no mechanical fan. Had 87mm liners for about 2.2L displacement, and a Modine radiator core with no crank hole. Didn't need the fan at all above about 45 mph, and it would keep the motor cool even in 115F heat and stop-and-go traffic.

However, the same setup is not working so well in my TR3, so it's not always about the fan & radiator.

DeRale makes a nice adjustable fan controller, with a control probe that just pushes into the fins of the radiator. It also has an input for an override switch if you are so inclined. Seems like that might be a good first step for your problem, Dion.

It also might be worth having a look at the water pump impellor. Although not a common problem, they do sometimes manage to erode away until the pump just doesn't move enough water at low engine rpm.

 

[Geo Hahn]

...look at the water pump impellor... they do sometimes manage to erode away until the pump just doesn't move enough water at low engine rpm.

And there was a time when some aftermarket pumps were supplied with much shallower impellers than original.

 

[MarshgrassA]

Ian,
So far my only overheating issues are with the driver not the car! My 67 TR4A seems to do much better than me in this heat with the stock stuff. I do have the extra electric fan on my MGA but since it came with that I can't compare the before but it does help in stop and go traffic.
Hopefully cooler weather is coming in a month or so.......

Cheers,
Irene

 

[DanB]

I put a TR6 fan on mine, the one with 7 blades I think, and it has helped. No electric fan yet.

Dan B

 

[TR3TomG]

I also had questions about the accurancy of my temp gauge. Picked up a cheap infared temp gauge on Ebay (about $10) and used it to check. Well worth the money, condsidering that it really worked.

Regarding replacement of the thermostat - I put in a sleved model from Moss (about $100) and it didnt seem to make a difference. The gauage inticates about 185 degrees almost all the time, except on hot days in traffic or stopped at a light when it will then climb a bit. I am thinking of putting an electric fan in front of the radiator with a manual switch. I am very reluctant to do much more. Any thoughts or other suggestons?

 

[martx-5]

...The gauage inticates about 185 degrees almost all the time, except on hot days in traffic or stopped at a light when it will then climb a bit. I am thinking of putting an electric fan in front of the radiator with a manual switch. I am very reluctant to do much more. Any thoughts or other suggestons?

If it ain't broke, don't fix it. If it's running 185 most of the time, then everything in the cooling system appears to be working properly. Even in the best of shape, the cooling system in the TR3's is just about adequate. Putting in an electric fan for those times when it really get's hot and your stuck in traffic is a good idea and will help you keep your cool also without having to worry about the engine temp creeping up.

 

[Geo Hahn]

...I am thinking of putting an electric fan in front of the radiator with a manual switch. I am very reluctant to do much more. Any thoughts or other suggestons?

I added the aux electric fan w/ manual switch and find it helpful in slow traffic. The rest of the system was stock (crank hole still in place) until I switched to a tropical fan. In my seat-of-the-pants judgement that made a big difference. My driving often invloves going up a mountain inhot weather where traffic can hold my speed down to 30 mph or so -- that tropical fan seems to keep the engine decidely cooler than the stock fan used to.

 

[TR3TomG]

I have done a bit of research, and the name Hayden for the brand of fan most used seems to keep coming up. Apparantly, that is the brand that Moss sells.

If anyone has any thoughts on a fan brand (and size) that might be best for my TR3, Id appreciate your advice on this. I intend to use this as a "pusher" (i.e., in front of the radiator). Also, is a 12 inch fan the way to go, or will a 14 inch fan fit / work best?

Many thanks for the advice!

 

[MichaelG]

Do you have the stock fan on the car? As someone else mentioned, I also installed the yellow 6-7 blade plastic TR 6 fan on my 4A and found it to be very effective..assuming of course that the rest of the system checks out OK.

 

[Geo Hahn]

...If anyone has any thoughts on a fan brand (and size) that might be best for my TR3, Id appreciate your advice on this. I intend to use this as a "pusher" (i.e., in front of the radiator). Also, is a 12 inch fan the way to go, or will a 14 inch fan fit / work best?

I use a 12" as a pusher -- it is just an inexpensive one from the FLAPS but had the same CFM claim as the Hayden and came with a lifetime warranty.

I think a 14" would be wider than the radiator.