Running hot/Overheating

[Bob_Spidell]

Yeah, I know this one's been beat to death, but I came across this article from the latest Hagerty's glossy. I think it sums up the issue nicely, and might be of help, especially with newcomers to the Forum (who sometimes seem to join just to ask this question). Incidentally, I just inherited a '65 Mustang with 289 that has the 'coolant flow' problem--there's plenty of space in the engine bay--and I think there's consensus that Big Healeys have an 'airflow' problem.

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[BOBBYR]

Hi Bob, I hope you take this question in the right way as I am not trying provoke you . That being said , here goes . The day your Healey was built and brand new , do you think that it was prone to overheating when either driven hard or idling in heavy traffic ? Being a mechanic my whole life , I remember when these cars were new and riding the streets and don't remember them having constant overheating problems . Just wanted to get your opinion . Thanks , BobbyR

[Keoke]

Well back then when the cars were new, the ambient air temperatures was lower and so was traffic density.

Over time these things changed and any margin the cars had was probably over ridden I think.

SOnow:

Big Healeys have an 'airflow' problem. Yep BOB

Today on the west coast if you do not at least have:

1 Upgraded Radiator
2 Six bladed fan
3 Coolant overflow bottle

I use Volvos pressurized design.

U gonna over heat-

[RAC68]

Hi Bobby,

Although my memory is not as sharp as it was but in its first Summer of existance, a buddy and I took my new 4-month old BJ8 Phase 1 on a weekend trip that ultimately lasted for well over a month and rambled from cost to cost and back. Living on the NJ side of the Lincoln Tunnel at the time, traffic and slow progressing city congestion were not uncommon frustrations and, when added to City Summer Heat, would stress most vehicle cooling systems, and drivers, of the day.

At the time, my new Healey was merely equipped with the factory installed yellow 4-blade metal fan and standard radiator. However, to compensate for the lack of cabin cooling, we dressed for the summer heat and took great advantage of sandals and shorts. Also, we did raise the top and lower all windows (including rear window) when driving through more exposed and sunny areas of the country.

I have set this stage because, during my first few years of new Healey ownership, I do not remember even 1 instant of overheating … even though I do remember having to add coolant to make up for liquid I left on the asphalt and pulling over when the foot well became too hot to continue. Yes, I overheated, but not my Healey.

As I see it, your recollections match my own,
Ray(64BJ8P1)

[Bob_Spidell]

Hi Bob, I hope you take this question in the right way as I am not trying provoke you . That being said , here goes . The day your Healey was built and brand new , do you think that it was prone to overheating when either driven hard or idling in heavy traffic ? Being a mechanic my whole life , I remember when these cars were new and riding the streets and don't remember them having constant overheating problems . Just wanted to get your opinion . Thanks , BobbyR

Me? Provoked? Nah ... just misunderstood .

My BJ8 has an engine freshly rebuilt by an excellent mechanic (170PSI+ on all cylinders), an uprated 4-row (I think) or Excel-cored radiator, a Texas Cooler fan, Pertronix Ignitor and is as well-tuned as I can get it. It seldom overheats at speed; the highest I've seen is pulling up the long grade on I15 from California into Nevada on a warm (90degF) day. Last I did this, I saw close to 200degF on my (calibrated/adjusted) temp gauge. Highest I've seen is 212degF pulling up the Panamint Mountains out of Death Valley on a 115degF day (we had to turn the heater on full blast to keep from boiling; there were several newer cars on the side of the road with their bonnets up). My BN2 is bone stock except for an uprated radidiator and Pertronix ignition, and behaves more-or-less like the BJ8, but I haven't driven it nearly as far as the BJ8. Timing on both cars is set to spec with an advance meter.

My biggest concern is stop/slow traffic, where the temp gauge rises steadily until I get moving again, then it cools down quickly. I had a seven-bladed flex fan on the BJ8 for a while and it helped in slow/stop traffic, but was so noisy I finally replaced it with the Texas Cooler. From all I've heard and read, on this forum and the email list, this problem is common. The consensus it that the Big Healeys don't get enough airflow through the engine compartment, hence the mods like 'scoops' in front of and baffles to the sides of the radiator, hood louvers, side vents, electric pusher fans, etc.

My take is these cars have always had this issue, they were perhaps more 'accepted' as we didn't expect as much performance and reliability from cars of that era and took overheating, etc. in stride. The early Mustangs were known to overheat as well, and our '65 behaves much like my Healeys. A Healey owner on the email list informed me that he solved the problem in an early Mustang he bought for his daughter with an aluminum radiator; I may take this approach as early Mustangs aren't all that rare, I'm not that concerned about originality, and it it really needs a brake upgrade as well (my dad was a factory rep for Ford and confirmed these were known issues with these cars). My '96 Ford Ranger--with the 4.0L 'Cologne' engine ('German steel')--had a defective thermostat from the factory and never reached running temperature until I replaced the thermostat (which still bounces around erratically).

I didn't own a Healey when these cars were new--although the seeds of desire were planted--but I recall hearing about numerous issues with most British cars of the period (and still hear them occasionally, though my BJ8 has over 200K hard miles on it and only stranded me once, when an otherwise well-built water pump blew its bellows and two replacements from a usual parts supplier were defective). But, to answer your question, based on my experiences and other on this forum--overheating issues are perhaps second only to oil and tire discussions--I believe overheating issues are innate to Healeys and a lot of older cars, they just weren't noticed at the time (but overheating was a common problem). My dad told me that he handled a lot of customer complaints about 'oil pressure gauges that moved up and down'--your average owner didn't understand that oil pressure at idle should be lower than that at 3,000 RPM--and this, along with cost, was why we got nothing but 'idiot lights' for many years. I am suspicious that in all my more modern cars--2000 Lincoln, 2008 and 2019 Mustangs--the temp goes goes quickly to the exact center of the range and stays there (are the cooling system and thermostats really that good?). Have the manufacturers really mastered heat control in modern engines, or have they just programmed their ECUs to show "all's well" no matter what? I was pleased to see my new Mustang has both oil pressure and engine vacuum gauges that behave like they should but, ironically, I'm too busy playing with all the electronic crap to notice .

On thing that could explain the difference for 'way back when' and now is that new engines, with clean blocks and coolant passages, were less inclined to overheat. But, I think most of us have rebuilt our engines at least once and probably had the blocks hot-tanked.

How does your car behave in Jersey? Last time I was there, probably 15 years ago, it got pretty hot and humid and you had your share of crappy traffic.

ps. Keoke makes good points that I hadn't considered before. I don't recall traffic jams 'back in the day' like we seem to have daily now.

[Michael Oritt]

I agree with Keoke ("Well back then when the cars were new, the ambient air temperatures was lower")--the problem is not a result of our cars' design but of global warming. We are all screwed.

[Healey Nut]

So when you have a car whos cooling fan speed is dictated by the speed of the engine and also a car whos front end is designed to have air pushed through it to cool it ,,,,,,,just how did you expect it not to overheat ?
My temperature guage starts to rise as soon as you hit a red light even with new recored radiator and six blade fan .
My feet get cooked when driving long distances in high ambient temps even with dynomat under the carpets etc etc .
I have just learned to drive the car differently , anticipate light changes to avoid long waits etc .I even drive with my left foot once I get cruising to tuck my right foot away from the heat for a bit .
On really hot days when its very humid I simply say sorry to the Healey and take the Aston out with the AC instead .

[RAC68]

Well back then when the cars were new, the ambient air temperatures was lower and so was traffic density.

Although I do agree with Keoke and Michael in the existance of Global Warming, Conjestion has always been present where I lived when my Healey was new. As many who have traveled on the NJ side of the Hudson River, it is more densly populated and traffic conjested then MidTown Manhattan which it is accross from. Yes, over the last 50 years the area did increase in traffic ... more then it did in population, however, Summers have always been HOT and I expect the average increase in global warming for the area did little to further its effect on the Healey cooling system.

Lets face it, although our Healeys have the look and sound we all love, it is the recipiant of bad cooling design. Its porous radiator bulkhead that provides easier exit radiator air forward for hotter and hotter recirculation promotes temperatur increases at a traffic light. Add the lack of fan shroud to deminish the efficiency of the fan and, when moving, the buildup of high pressure that builds to an escape block under the bonnet and can even be monitored by watching the temperature gauge increase at speed.

Maybe my youth, enthusiasm, and pride had shaded how my Healey handled heat in the beginning or maybe it was really more tolerant to temperature when new. Keep in mind that with a fresh radiator, clean engine water passages for heat transfer, and new engine parts that allowed the view of good pressure but better flow and flow when using the more common 10W30 or 40 weight oils that carried away internal engine heat more effectively then our now common 20W50 today. Yes, there are reasons for our Healey's running cooler when new then they would 50 years later and, from my perspective, Global Warming and increases in traffic Conjestion are much less then major factors.

Just my thoughts,
Ray(64BJ8P1)

[Bob_Spidell]

A conundrum I didn't mention--but have done so here previously--is that both my Healeys run cool on cool days; i.e. on a relatively cool day say, 50degF often the engines will never reach nominal temperature (except, of course, stuck in slow traffic or at a light for a long time). I've tested the thermostats and tried different ones but the car won't get up to the thermostats' setpoint (180degF), although on a warm day on the open road they get there and (mostly) stay there, so the thermostats are opening properly. According to some law of thermodynamics, I suppose, combustion and friction should cause an engine to keep heating up until the thermostat lets the coolant flow, but sometimes that doesn't happen. That might be more explainable on a light, aluminum block engine which should dissipate heat well, but on a big cast iron lump it makes no sense. My BJ8 has a modified thermostat that at least partly closes the hole that lets coolant circulate through the head, but the BN2 does not and both behave the same.

[dcarlg]

Ray,
I'm glad that you mentioned different motor oil viscosities.
I recently came across an article discussing how 40 and 50 weight oils retain heat more than thinner oils, which makes sense.
However, I continue to read how 20W50 is THE (only?) recommended oil for our engines.
Has anyone tested the effect of different oil viscosity on their Healey's operating temperature?
Or does the oil pressure drop too much, even in freshly rebuilt motors?
I decided to try Mobil 1 0W40 in my rebuilt motor. 540Ratblog rates it in the top 10 and it has a moderate zinc level.
Just need warmer weather to swap engines. And more time for my broken wrist to heal...
Thanks for this discussion.
Douglas

Full disclosure: Yes, I'm retired and have too much time on my hands.

[steveg]

A conundrum I didn't mention--but have done so here previously--is that both my Healeys run cool on cool days; i.e. on a relatively cool day say, 50degF often the engines will never reach nominal temperature (except, of course, stuck in slow traffic or at a light for a long time). I've tested the thermostats and tried different ones but the car won't get up to the thermostats' setpoint (180degF), although on a warm day on the open road they get there and (mostly) stay there, so the thermostats are opening properly. According to some law of thermodynamics, I suppose, combustion and friction should cause an engine to keep heating up until the thermostat lets the coolant flow, but sometimes that doesn't happen. That might be more explainable on a light, aluminum block engine which should dissipate heat well, but on a big cast iron lump it makes no sense. My BJ8 has a modified thermostat that at least partly closes the hole that lets coolant circulate through the head, but the BN2 does not and both behave the same.

Bob, My car functions like your description.

Lately did 55 & 35 mile freeway drives in <60 ambients and temp was a hair above 170 indicated while running. I have a 180* sleeved robertshaw thermostat which opened at that temperature when I tested it a couple of years ago. Radiator overhauled a couple of years ago; <4k on rebuilt engine.

[HealeyRick]

Although geared to the V8 motor, this is a pretty good read for tackling cooling problems in the Tiger: https://teae.org/cooling-the-sunbeam...om-chuck-king/

[Michael Oritt]

Ditto for my 100 re the phenom that Bob describes: though I don't understand why a 180 thermostat will not produce 180 or higher temps on a cool day that is the way it is for me as well.

As to what Ray says, cooling systems lose effectiveness with age as radiators and blocks build up scale, cutting down on cooling efficiency. There is more traffic, the roads are hotter and whatever tolerance for discomfort we may have in youth also goes south as we age and increasingly get used to air-conditioned environments.

I'm currently reading Tom Friedman's book Hot, Flat and Crowded It was written a few years back and points to a bleak future which seems to be coming true. Without getting into political discussions I think it is undeniable that we as drivers of highly polluting and gas guzzling vehicles are not doing much to make things better. I believe the expression is "Hoist On Your Own Petard".

[Bob_Spidell]

Gotta be something to due with heat convection due to ambient/engine heat delta. All we gotta do is air-condition our engine bays to keep them runnin' cool!

[BOBBYR]

Hi Bob , The reason I asked is because after reading the article you posted , it got me to thinking of all the modification ( no matter how slight ) we all put in to our healeys . Just from the responses from the guys here , I think you've backed that up . Fuel different , oil different , thermostat opening temps (160 or 180 ). Anyway , this forum has really been a great help to me over the years and I really enjoy reading different views from you and the gang . I guess we're just all working to get that perfect ride . Thanks for all the replies , BobbyR

[RAC68]

Hi All,

Michael,
Yes, I also believe global warming to be a fact as strongly as I believe new pristine engines will allow better heat transfer to the cooling systems.

Douglas,
I too intend to try a lower viscosity oil, probably 10W40, as a more flowing alternative to my previously used of 20W50 or even my present use of 15W50. Back when my Healey was new, 10W30 was the most commonly used automotive multi-viscosity oil and 10W40 represented a new oil alternative (to me} that could better handle the Healey's more substantial heat generation (viewing the oil pressure gauge as the indicator of performance). I say more substantial Healey heat as my previously car (a mildly engine-modified and customized 1958 Pontiac convertible with 389 CID High Compression V8) seemed perfectly happy being mid-Summer lubricated by 10W30 ESSO Oil and never had an internal failure or heat problem.

I am presently running and was very happy with Mobile 1 15W50 but found this oil (differing from most other Mobile 1 viscosities) to only register a Modest Ware Protection rating with a PSI of 70,235 psi. Although cold starter crank speed has greatly improved from my previous use of Valvoline VR1 20W50, gauge-registered oil pressure seems to have been maintained (a possible drop in gauge-indicated pressure, but minor).

This Summer, I will be trying Valvoline 10W40 MaxLife High Mileage to determine how this thinner oil will register on my gauge and if it would noticeable handle heat better. Since my engine has its original lower end components, this high mileage oil, with a ware protection rating of Outstanding at 103,840 PSI, hopefully would allow good flow under a reasonable level of monitorable gauge-pressure.

Once changed and tested, I will report back,
Ray(64BJ8P1)

[steveg]

Hafta say, one of the things I really appreciate about this Forum is as a refuge from the 24/7 bombardment of politics. Mostly it succeeds.

[AngusSaunders]

Let me first point out, I have never driven a big Healey. I hope to if I live long enough. My experience has been MG's and I remember switching feet to cool the right one for a while. Given that I have a few questions. Can an oil cooler be fitted to the big Healeys and if so does that help the over heating situation? Could a larger capacity oil pan be fitted, maybe aluminum? Is it possible to install a thermostatically controlled electric radiator fan? These would be modifications undesirable to those purist but not to those looking for functionality. Please excuse my ignorance but this is an interesting discussion.
Angus

[steveg]

Welcome to the Healey Forum, Angus. Yes to all your questions.

[Guy Marshall]

Apologies if this has been linked already in this thread but https://www.healey6.com/Technical/I%...COOL%20Car.pdf seemed like good advice to me.

My 100/6 runs fine in France where we often get 35C+ temps though as I have no carpet etc at the moment so the smell of burning rubber from my feet can be off-putting.

The main issue I have is running uphill. The region is pretty hilly and if I park at the top things get hot. I have no mechanical fan but rely on a kenlowe, and I have a simple unpressurised overflow tank. I have a new waterpump and side vents to fit this year, as the issue seems to be airflow through the engine bay.

Anyhow Ray's ideas are well worth considering.