Overheating

[Pete3000]

Have read many informative posts on overheating problems here on the forum. Living in south Florida, the summers are just brutally hot and have always had trouble keeping temp under 200. Have a 6 blade fan and an original but clean radiator with the air deflectors in front. Also a 7 lb. cap from moss. When idling in any traffic, temp creeps to 212 and up. After shutting engine it continues to rise to 230+. Is this rise normal and what would be the best thermostat for my extremely hot weather application? Sleeved, unsleeved? Also, I have read about blocking or partially blocking a bypass port so coolant flows to the radiator. Where is this bypass port and how do I block it or should I? Any help would be greatly appreciated.

 

[67BJ8]

Pete,

My Austin Healey 3000 has a totally rebuilt engine, new water pump, 6 blade fan, Moss cap, and a rebuilt upgraded radiator. Driving it in 80 to 90 degree weather the temp stays at 180 degrees. However, driving in a parade at 80 degrees that lasts about an hour will cause the engine temp to rise slowely to 210 to 215 degrees. I think that it is the nature of the beast. Also, the interior gets #%*&^ hot! My brother-in-law has a beautiful 1958 100-6 that does the same thing when in a parade or a traffic jam. I am not familiar with the bypass port recommendation.

Larry

 

[Keoke]

Hi your Healey is about what can be expected when using the standard radiator. You need to have your radiator upgraded to a four core serpentine core. This will increase the cooling capacity considerably. To take advantage of the Bypass port a thermostat with a sleeve is required to block it off. These are available from British Car Specialties and others. _Ewiw--Keoke

 

[Bob_Spidell]

Have tried all of the above and have a 4-row 'Excel' radiator core and a small shroud around the (Texas Cooler) fan. Temps stay around 180deg when cruising but always creep up at idle on a hot day. The one thing that worked on the idle temp issue was a Hayden 7-blade stainless steel flex fan. That thing really moved the air, especially at idle, but I got tired of the howling noise it made and put the Texas Cooler in. I have a sleeve on a 180deg Robertshaw thermostat and, frankly, don't think it buys you much (maybe a degree or two at most).

With a std. 7-lb cap you won't boil until either 226F or 233F (forget if you get 2 or 3 deg per lb). The rise in temp when you shut down is called 'latent heat,' which is kind of a misnomer because when you shut down the engine is still producing the same amount of heat but it's not being dissipated by the cooling system. Perfectly normal--that's why on cars with thermostatically controlled electric fans the fans run for a bit after shutdown--but 230deg seems a bit high (then again, I haven't driven my Healey in FL so that might be normal).

I'm convinced that not only were Big Healeys under-radiated but they also trap too much engine heat in the engine bay. I put header wrap on my downpipes and there's more heat coming out the exhaust that presumably would otherwise be heating up the engine bay, but can't say for sure if that's helped coolant temp. I think ceramic coatings--e.g. JetHot--applied to both the manifolds and downpipes should help a bit (your feet might get even hotter, though :wink:. Also, in FL you shouldn't have to worry too much about freezing and could run pure (distilled) water--with Water Wetter or soluble oil to lubricate the pump--in the summer. Water does a better job of heat transfer than antifreeze. I suspect that would buy you a few degrees.

 

[ArtQ]

Your temps don't sound all that bad. Is there still flow through the heater---some owners close that part of the system off? Also, some have had the radiator redone to include a different neck (required) and 13lb cap.

 

[John_Progess]

I had the same situation with my 64 BJ8 so I purchased the blanking thermostat from Moss and I also constructed a deflector that extends below the shroud (about 2") at about the same height as the anti sway bar and angled back and up to the radiator fins. It is bolted to the inside of the frame rails using the same threaded inserts as the bumper supports. At about the same outdoors temp as before my water temp now gets to about 190 deg. I don't know which modification helped the most but I gained approx 10 to 12 deg cooling. My biggest concern was trying to get the internal cab temperature as low as possible. Have a good day!

John

 

[John_Progess]

I had the same situation with my 64 BJ8 so I purchased the blanking thermostat from Moss and I also constructed a deflector that extends below the shroud (about 2") at about the same height as the anti sway bar and angled back and up to the radiator fins. It is bolted to the inside of the frame rails using the same threaded inserts as the bumper supports. At about the same outdoors temp as before my water temp now gets to about 190 deg. I don't know which modification helped the most but I gained approx 10 to 12 deg cooling. My biggest concern was trying to get the internal cab temperature as low as possible. Have a good day!

John

 

[Pete3000]

Sounds like a great idea. I like the deflector idea. I am running water wetter but also put about a quart of straight antifreeze. Maybe I'll drain and go with straight water + water wetter. My concern was with proper lubrication, that's why I used some antifreeze. Don't really know if heater valve is open as the shut off arm is broken off at the engine. Need to replace.

 

[TimK]

How do you know you have clean radiator. I thought mine was clean but had exactly the same symptoms. I also had the symptom of a quick rise in temp. at freeway speeds. It turned out I had a soft mud-like plugs in about 40% of the radiator tubes. This was only visible when the upper tank was taken off. The coolant was clear and clean looking. I had my original radiator re-cored with 14 fins per inch in a serpentine pattern. You will have some temp gain in a long idle situation in hot climates. As long as you have no boil over, the only negative is thinning of the oil and reduced oil pressure.

 

[John_Progess]

Pete3000,
If you use straight water, be sure to add some corrosion inhibitors, available at your local auto parts store. The deflector only took about an hour to build out of .030" thick material. Have a good day!

John

 

[Patrick67BJ8]

From the manufacture of anitfreeze...50% antifreeze and 50% water.
I use a thermostat from BCS, Texas Kooler, electric fan with a thermostat control. I also run AC with rotary compressor and the radiator was rebuilt here in Dallas and capacity was improved 25% to 30%. My engine temp is very good at 180. In city traffic it creeps up to about 195. It is normal to have over 200 after shutting off the engine. Some guys like to have their electric fan set to run until the temp is below 180, but thinking about that, it is only for the raditator and the engine is still very hot. Maybe I'll get a shroud from BCS when the engine goes back in the car?!
Patrick

 

[TomFromStLouis]

I have not overheated since I flushed my system and added a small bottle of <span style="font-weight: bold">Water Wetter</span> to the mix. Somehow it makes the fluids transfer heat more efficiently than without it; it works! Available at my local AutoZone.

 

[BabaKahawa]

My healey does the same as yours, runs about 212 in the hot New Mexico summer, hits 230+ after I stop. But if the car does not overheat and dump fluid you should be fine. It's seems normal.
I think the real concert is the heat from the engine to the driver on those hot days.
Happy Healey
________________________
Jolly - 1958 BN6
1972 BMW 3.0 CS

 

[Kobus Brink]

I had the same situation with my 64 BJ8 so I purchased the blanking thermostat from Moss and I also constructed a deflector that extends below the shroud (about 2") at about the same height as the anti sway bar and angled back and up to the radiator fins. It is bolted to the inside of the frame rails using the same threaded inserts as the bumper supports. At about the same outdoors temp as before my water temp now gets to about 190 deg. I don't know which modification helped the most but I gained approx 10 to 12 deg cooling. My biggest concern was trying to get the internal cab temperature as low as possible. Have a good day!

John

 

[DerekJ]

Thermostats control how fast the engine gets up to operating temperature but have no effect on how hot the engine runs. The improvement is probably the result of your airflow modifications.

 

[roscoe]

I have no numbers except that I don't seem to have these high running temperatures, and I think that two modifications I've incorporated make a significant difference: Hood louvers and oil coolers. I certainly understand that although some have louvered hoods on 100-6 and 3000 cars, it may not be a look that is as popular as it is with the 100. However, they work. On a hot, still-air day I can see the heat waves exiting the louvers, heat that otherwise is trapped to some degree (no pun intended) under the bonnet. The other is an oil cooler I have mounted just behind the grille and in front of the radiator bottom. Oil is for cleaning, lubrication and cooling. Dumping some of that heat has to help.

 

[Randy_Gay]

You may want to fabricate a coolant recovery / catch tank. This will require a second seal on the radiator cap. Headed to Snowmass way back when, we used an old racer trick and switched the bolts on the back of the bonnet to raise it up. No problems after that.

 

[bob hughes]

I know that we have cooler weather over this side of the pond, but I did have the over heating problem until I refurbed the engine, removed all the plugs and used long and short rods to remove the crud inside the block, gave it a good flush out and back flushed the radiator. The head had been chemically cleaned ( twice ) when it was converted to unleaded, twice because one of the inserts fell out. Put one of the Texas cooler fans on ( the British equivalent ) and have had no trouble since. I do agree that a bigger radiator will make all the difference though.



Bob