• Hey Guest!
    British Car Forum has been supporting enthusiasts for over 25 years by providing a great place to share our love for British cars. You can support our efforts by upgrading your membership for less than the dues of most car clubs. There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Upgraded members don't see this banner, nor will you see the Google ads that appear on the site.)
Tips
Tips

TR4/4A TR4 Over Heating

Share this page

KVH

KVH

Obi Wan
Silver
Country flag
Offline
I'm fine now that it's winter. But two questions or issues:

1) my mechanic swears that in a hot western climate using a 160 degree rather than a 180 degree thermostat will make no difference. He says that the car will reach 185 degrees and open wide in fifteen minutes anyway, thereby making the difference in thermostats irrelevant. Do you folks out there tend to agree or dis /bcforum/images/%%GRAEMLIN_URL%%/yesnod.gifagree?; and

2) what difference would a new "improved design" water pump make? Any at all?

PS I have an auxiliary fan, and that has apparently saved me from overheating.
 
Hi There Kentvillehound;

Personally; I would & have always gone with the recommended thermostat for the season. Does it make it difference; Who knows but its a "Cheap" way to find out.

Do you have a radiator shroud attached? I had a TR6 that did`nt & always overheated. Added the shroud & problem solved. Also; an "Inexpensive" addition.

This is probably a silly question but when was the radiator last "Boiled Out"? /bcforum/images/%%GRAEMLIN_URL%%/confused.gif I would have that done automatically.

Should you do or have the above mentioned parts; I don`t believe an upgraded water pump would be necessary.

Best Wishes;

Russ /bcforum/images/%%GRAEMLIN_URL%%/banana.gif
 
Aloha,

I suspect that your summer climate is hotter than here in Hawaii. I have used a 165 degree F thermostat but changed back to a 180 degree F one because it took so long for the car to come up to operating temperature with the 165. My experience is that even with the lower temperature version eventually the temperature gauge will read about 180.

I have been using the stock water pump and it seems to do the job for my car. The improved pump has a more efficient impeller design so I think it can theoretically move more gallons per minute than the straight vanes of the stock pump. However, either pump can only move as much coolant as the passages in the engine, the thermostat and radiator will allow at 4 to 7 psi. In my opinion, I would only change to the new pump if the installed on failed.

The radiator shroud does a good job of forcing most of the air into the grille going through the radiator. At road speed the ram air should effectively cool the coolant.

These are two things to check, condition of the radiator fins and sediment in the engine block.

It is important to also check the exterior of the radiator. The fragile fins that are connected to the tubes do the cooling. If they are corroded, broken loose or full of road grime and dead bugs heat transfer will be reduced greatly. Re-coring a good brass radiator is most often a lower cost option than buying new one. I remove it myself and take it to the shop and have it back in less than a week and the cost is about $250.

Sediment build up in the engine block can also decrease the efficiency of the cooling system. I don't think most over the counter radiator flushes do much to solve this problem. I periodically poke a wire through the rear engine block petcock to agitate the sediment to get it moving. I remove the hoses to the radiator before doing this so I don't move the sediment to the radiator.

Although I do have an electric fan I rarely need to use it.
 
Kentvillehound said:
1) my mechanic swears that in a hot western climate using a 160 degree rather than a 180 degree thermostat will make no difference.
Click to expand...
Depends on the circumstances, IMO. If you are talking about steady-state driving, then I agree with him. But there are some circumstances where it can help. For example, if you've been driving at high speed (with the thermostat controlling the water temperature) and then stop suddenly (like pulling into a rest area on the Interstate); the coolant gets hotter because there is still excess heat in the cylinder block and head, but the coolant is no longer circulating through the radiator. In that case, running a lower Tstat can give you more margin before the coolant boils.

But I run a 185F, and solve that problem by letting the engine idle for a minute at a rest stop.
<div class="ubbcode-block"><div class="ubbcode-header">Quote:]2) what difference would a new "improved design" water pump make? Any at all?[/QUOTE]Haven't tried one myself, but I've heard from several people that it helped keep their engines cool in traffic.

I even bought a 6-blade pump for my TR3A, but never got around to trying it. Recoring the radiator made all my overheating problems disappear (even in 115F ambient) so I quit working on them. And tried to avoid driving in 115F !
/bcforum/images/%%GRAEMLIN_URL%%/grin.gif
 
I do run the cooler tstat just because I think it buys me a little more leeway in situations that put a strain on the radiator's ability to cool: e.g. going up Mt Lemmon or being stuck in traffic on a hot day.

That said, I doubt that an overheating car will be cured (or markedly improved) by simply changing the tstat.

Leading suspects here would be some blockage or other inefficiency in the radiator or some blockage in the coolant jacket in the block.

Next time we're on the same drive we can compare some data. I always have an infared thermometer with me, might be interesting to see what the diffecence is between the temperature of your radiator inlet and outlet hoses.
 
I put a 160 deg. thermostat in my Miata when I installed the supercharger, because it came with the kit. The only thing I noticed was that the car took longer to get up to temperature. Once the thermo is open, it can't make the engine run cooler. If conditions are such that it runs hot with a 180 deg thermo, a 160 deg will not help. It just may take longer to get there. If the temps start pushing 200 or above, both thermostats would be wide open, so the 160 has not done anything to help the situation. I put the 180 back in the Miata so it would warm up faster, and have not noticed any other differences.

BTW, Ken Gillanders at British Frame & Engine mentioned to me that the six bladed TR water pump prevents cavitation at higher rpms, and generally performs better overall. Besides having the two extra vanes, they are curved rather then being straight on the radius. This helps probably more then the extra vanes. I need a new water pump, so I've got one of those on order from him.
 
I have a 4A and always had an overheat issue as soon as I got into a line up or slow traffic. Solved the problem by using a 160 therm. and putting a small electric fan into the shroud in front of the rad to push air through when needed. The fan is on its own therm. coupling and you set the temp. for the season. Easy to install and there is no real draw on our electrical system. No more tea time in line ups or outings.

Cheers
 
Run 2/3 water and 1/3 anti-freeze, add some water wetter, you should be able to run roughly ten degrees cooler on this mixture.

Make sure your shroud is in ggod shape.

I agree with those who say the thermostat isn't really the issue, biggest difference it would make is the higher temp unit would allow the heater to work better in winter.

Which was an issue when we drove the cars year round, prbably not so much for most of us now.
 
Back
Top