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MG MGA - Oil cooler placement

My 1500 A has been running hot so I'm looking for ways to help cool it down. My oil cooler was or is mounted
on top of the pan infront of the radiator. I'm trying to mount it below where it shows in the books but have
run into a possible problem. If I mount it there I will
not be able to use my crank to hand start if I need to.
Could I hang the cooler lower by using longer bolts and extension pipes in the four mounting holes, say just enough so the crank can clear the cooler? Any other suggestions would be appreceiated.
Tom Peotter

The correct placement of the cooler is on top of pan in front of the radiator. Only the oil lines run under the pan.
John H

A few questions: 1)Are the large hoses to the heater and carbs. in place? 2) Do you have the felt on the under side of the hood? 3) Do you have a replacement radiator? The correct answers for better cooling: 1) yes, 2) yes, 3) No
David Werblow

To run an oil cooler under the pan you would need to remove the bumper and cut an air hole in the valance. The instalation per factory manual is pictured here.


R J Brown

I'm not understanding why I would have to cut a Hole in the valance to hang the oil cooler under the valance
using longer bolts with spacers between the bottom of the valance and my cooler? The space created would only allow the hand crank to slip between the cooler and the bottom of the valance thus allowing more air the help cool my radiator.
Tom Peotter

Unless you cut holes in the front valance the oil cooler will not get a stream of air to cool the oil.
John H

I wasn't aware that there was no wind under the car...
Thanks. Tom
Tom Peotter

Good grief!!!!
Marvin Stuart

I guess I did not appreciate that response from you Marvin but coming from a "non-member" I guess I do understand...Sincerely Tom Peotter
Tom Peotter

Tom, Marv. has driven his '60 MGA from Connecticut to Oregon for GT-29 and just returned from British Columbia, GT-31. He has restored and maintains his own cars as well as helping out others in our local club. He is truly the type of MG owner that makes MG the "Marque of Friendship."
David Werblow

Tom,

I think we have a failure to communicate here. Pardon me if I have misunderstood but, the valance that needs the cut out is under the bumper, and not the valance that sits in front of the radiator. I have mine under the radiator valance and cut two rectangular holes in the valance under the bumper and attached grills over the holes. Painted body color they don't show unless you look for them and even then they have a kind of works car look to them.

It also sounds to me like you are suggesting that the under mounted cooler be spaced down enough to allow for the use of the hand crank - That solves the only issue I have had with my installation - good idea.

Randy Myers
'59 roadster, coupe
Randy

Tom,

I recall reading that the oil cooler doesn't play a significant role in lowering the engine (coolant) temperature (Maybe on Barney's website). Of course, the main source of the heat is the combustion in the head, which the coolant is intended to carry away and why the temperature sensor is in the head in the first place.

My '62 1600 MkII roadster, which has an oil cooler, had been running hot for many years, so last summer I finally decided to do something about it short of rebuilding the engine. I tried most of the recommended tricks adding one at a time to see if any one thing was the major factor. I was able to significantly lower the temperature - now running 185-190F (down from 200-210F), and found that each item I tried contributed some to the overall heat transfer efficiency. The items to consider are (order is my rough qualitative impression of descending order of importance and not scientifically demonstrated):

1) Raditator not restricted by corrosion or design. (I have a c. 1990 vintage raditor obtained from Moss and I believe it was made in China. It provided about the same cooling ability as the old, original, partially clogged radiator, but the replacement didn't leak.) [I also recall that a standard test is to measure the resistance to flow by removing the radiator, filling it with water, and measuring how quickly it drains.]

2) VERY, VERY IMPORTANT - Don't use an antifreeze mixture with more than 50% glycol, as water has much better heat transfer (thermal conductivity) characteristics. [Like many people, over the years I fell victim to the marketing strategy that relabeled glycol from "anti-freeze" to "coolant." I had gradually up the percentage to 2/3 glycol and 1/3 water to generate the largest range between freezing point and boiling point.] The reality is that water is the far superior coolant. The glycol provides protection by lowering the freezing point and raising the boiling point; however too much glycol and the thermal conductivity will fall faster than the boiling point is raised with the result that the solution boils - not good.

Radiators on modern cars much more efficient than those used in the MGA, so the mixture in a modern car is not as critical in transferring the heat from the engine to the radiator.

3) High Octane fuel and properly adjusted carburetors, i.e. not too lean. (Try Sunoco's street-legal 100 octane racing fuel at least once - if nothing else it stays fresh longer.)

4) Felt on bonnet above radiator

5) Whetting agent.

6) Proper thermostat (I tried the one that blanks off the bypass once operating temperature is reach - although it was only the earlier A's that used the bellows type thermostat

7) Carburetor and interior air hoses installed.

8) Proper radiator cap - though this is mainly for overheating protection

Other items I have yet to try are:

9) A shroud for the radiator fan.

10) Removing some slats from the grill (not a preferred remedy.)

Based on David's comment I might consider finding an alternative radiator. Anyone one have a recommendation based on flow or heat transfer measurements?
Steve K

Steve, a great "to do" list and a few things that I have yet to try. I have a similar situation to you. I have a Moss replacement rad and no oil cooler and I am running around 200-210 on "hot" days. It seems that the temp tops out when I'm on the highway at speed versus running around town in traffic. You mentioned thermostat versus blanking sleeve. I've just changed that as well but wondered what temp thermostat you went with .... I used a 165 degree and wonder if I shouldn't have gone with a 180 ... theory being that the water would stay in the rad longer and be cooled more efficiently ??? I'm also going to try the 50/50 mix too ... right now I'm probably 60/40.

Thanks for the ideas !!

Mike
1960 MGA
Michael Hosier

Tom, I'm curious as to what a "non-member" status has to do with any comments on this website. Marvin
Marvin Stuart

To Marvin, Its about the same stupid answer as you gave
to me, only my question was sincere not your response to my question.

Everything that Steve K. has listed I have done to my 1956 MGA that I have owned since College back in the early 70s. I have also added a shroud, added three additional cores to this radiator the same time tested. all the duct work is in place with mesh screens, felts pads, bent slats in grill 50-50 coolent, water-weater ect. ect. ect. I will be installing a nos water pump this weekend and I hope
this is my problem. I'am a member of NAMGAR for many years and have been to several events as well. I gave both my sons British cars, my oldest a 1959 MGA and my youngest a 1960 Bugeye. I do not need a comments like that from Mr. Marvin...Thank you all for your responses to my overheating problem with me and my "A". Tom
Tom Peotter

Tom,
I would look at things other than the oil cooler. If you have had your car this long and have had no problems with engine temp then it must be something else, unless of course you just installed the oil cooler.

Mark
M Gannon

Tom

To follow up on the comments on water being a much better coolant than glycol antifreeze, consider reducing the amount of antifreeze to whatever is needed for your temperatures. I am in Southern California and during the summer regularly encounter 100+ F temps plus a 1,000 ft elevation gain on the freeway on my commute home. I have gone to 100% distilled water with water wetter and a water pump lubricant, and only rarely have to slow down below my normal 70 mph cruise speed due to engine temperature. This approach is not a magic bullet but should provide you with another incremental improvement in the cooling. And of course when the temperatures start to drop toward freezing it is time to up the percentage of antifreeze.

HTH

Larry
58A
72 BGT



Larry Hallanger

Tom,
Steve K's list is right - #3 is important. I found a lean mixture to be the main cause of my overheating, and as yours gets hot when at top speed, I would think you may need to turn down the jet screws a few flats.Check also that you have the correct needles fitted. Look at the plugs after a hard run at top speed, ie, stop by the side of the road. They should be light brown.
I fitted an oil cooler some years ago - made no difference to the water temperature. I also have a rad shroud fitted, and found that it helps when idling, eg, in border line-ups.
I do have a question to pose to the MGA geeks out there - what difference does a 165 or 180 thermostat make to the running temperature? When the engine is hot, either of these will be fully open (they are either open above the specified temp, or closed below the specified temp) so water at 190 degrees (normal running temp) is fully flowing with either thermostat. The only difference is that one will open earlier, ie, the engine will get to warm up sooner. Let's have your comments, please.
I'll see you at Heritage in North Vancouver this Saturday, if you're going.
Peter.
P. Tilbury

Michael and Peter,

To answer your questions, first the question on the type of thermostat:

The thermostat I installed is Moss P/N 434-156. This thermostat is based on a bellows construction and in addition to an orifice that opens and closes to control flow through the main channel, it also includes a sleeve that moves to control flow through the bypass port in the head. Evidently this type of thermostat was used in the early MGA's, but was replaced in later MGA's by the modern style thermostat (regulated orifice, but no regulation of bypass). The modern style thermostat is much simpler, and therefore less expensive. Presumably the designers thought the cooling system was more than up to the task and were no longer concerned with the bypass flow.

The older style thermostat with the bellows and movable sleeve has the benefit that when the engine is at temperature all of the coolant that is leaving the head is directed to the radiator and none is shunted back to the engine via the bypass port. Consequently, all of the flow is going into removing heat from the engine. In contrast, with the later, modern style thermostat, there is no sleeve attached and some amount of the flow is always bypassing the radiator and being immediately returned to the engine. Note that the purpose of the bypass is to circulate water in the head when the thermostat is closed in order to prevent hot spots when the engine is running, but is not yet up to operating temperature.

Next the question on the effect of the thermostat temperature specification:

Regarding the temperature at which the thermostat opens, the steady state temperature the engine reaches is only influenced by the thermostat if the cooling system is so very efficient in removing and dissipating heat that the engine would run colder than is desirable for optimum combustion. Said differently, if the engine is tending to run too hot (say 210), then either the engine is generating more heat than it should and the cooling system is not up to the task, or the cooling system is operating below its intended efficiently. In both cases, regardless of the temperature that the thermostat opened (say 165, 180, or 195), in steady state the thermostat is wide open and the only (and small) influence it has is determined by the resistance to flow created by the size of the orifice that the coolant must flow through. (In principle removing the thermostat will improve the cooling efficiency of a system that is marginal; however, this is undesirable, as there are negative effects of having the engine not up to running temperature as quickly as possible, such depositing carbon soot and diluting the oil as a consequence of needing to run a richer mixture at lower temperature.)

Finally, the question of how quickly the coolant should move through the radiator:

Contrary to what you might first think, the coolant should move through the radiator as quickly as possible to dissipate the most heat.

Here's why. To begin, to first approximation the time that the water spends in the radiator doesn't influence the rate of heat transfer. One way to think about it is to first, imagine that the engine is generating an amount of heat (waste energy) each second and the heat needs to be removed (Of course, ignore the hot gases that are blowing out the tail pipe). Next consider a small portion of the volume of coolant (a cubic centimeter or cubic inch, as you prefer) that has been cooled by the radiator and is on its way back to the engine. When it gets to the engine, its temperature starts to rise. If the portion (small volume) spent a long time in the radiator, it necessarily spends a proportionately long time in the engine. Therefore the temperature of the volume of water entering the engine is low but rises very high before it leaves. The volume under consideration then leaves the engine and returns to the radiator where it enters very hot and is cooled back down by the time it leaves. (In this process we can assume that the average temperature in the radiator is sufficient to dissipate the same amount of heat that the engine is generating as waste heat, i.e. we've reached the steady state.) In effect, the volume of water is analogous to a bucket for carrying heat. Note though that based on having considered what happens to the temperature of a portion of coolant as it passes through the system, if we wish the maximum temperature of the coolant anywhere within the engine to not exceed a given temperature, call it T_maximum, then the average temperature of the coolant in the radiator is necessarily less than T_maximum.

Next imagine increasing the speed of the volume of water as it passes through the system. It spends less time in the radiator, but also less time in the engine. Therefore on each pass it picks up less heat from the engine and drops off less heat in the radiator than it would if it were moving slowly. Your first intuition tells you that this doesn't sound like a good thing. However, as it is traveling faster, it's also making many more trips between the engine and radiator than a slower moving volume would. The net result is the faster moving bucket moves the same amount of heat per unit time as the more slowly moving bucket, it just makes more trips back and forth within the same time interval to accomplish that. Now, the advantage of the faster moving coolant is that the temperature differences within the engine and within the radiator are less than if the coolant were moving slowly. This has two benefits. One is that the average temperature of the coolant in the radiator will come close to the maximum temperature permitted within the engine. Why is this good? It's optimal because the rate that the radiator can dissipate heat to the air flowing past it is proportional to the temperature of the radiator. The hotter the radiator, the more heat is dissipates per unit time. (Clearly the average temperature in the radiator can't be any hotter than the maximum temperature in the engine, so the best we can do is get the average temperature in the radiator equal to the maximum temperature in the engine, and this we accomplish by flowing the coolant through as quickly as possible.) The other benefit of flowing the coolant through as quickly as possible is that the temperature differences between the inputs and the outputs of the radiator and the engine are smaller, so consequently so are the thermal stresses and distortions.

Hence the conclusions to lower the steady state temperature are:
1) Reduce the amount of heat the engine is generating, i.e. tune it up and reduce friction.
2) Use a coolant that can absorb/dissipate the maximum heat per unit time, i.e. has the highest thermal conductivity – Use more water and less glycol. Use a whetting agent.
3) Don't restrict the flow between the engine and the radiator, for example, don't use a radiator that's clogged, don't use a radiator with too narrow plumbing (restricts flow and also diminishes heat transfer to the air), and don't allow the radiator to be bypassed.
4) Increase the radiator's ability to transfer heat to the air flowing into the grill, for example, increase the surface area of the radiator's cooling fins, install the felt over the radiator so the air can't bypass the radiator, adjust the angle of slats of the grill to allow more air to flow through to the radiator (I recall reading that the slats on some replicas were not angled sufficiently to allow the necessary air flow.)

Steve
Steve K

Steve .............. thank you !!

I've printed your note and added it to my shop manual. Thanks for taking the time to draft a very complete explanation.

Mike
Michael Hosier

I have a 82C thermostat in my set up. Car runs at 72C. I had a 70C thermostat. Car still ran at 72C. I had a Moss radiator and 70C thermostat. Car ran at 50C and always needed choke or a piece of plywood in front of the rad. When I had three Moss rads fail in the space of a year, I had the original recored locally, and now have no leaks and 72C steady. It is NOT a high performance core.
dominic clancy

I run a 180F thermostat with a blanking sleeve on an original radiator that was boiled and rodded about ten years ago. I have the felt hood piece and the grill slats are straightened a bit to help air flow. I do not have an oil cooler. I rarely ever get over 190F on the worst days VA has to offer. I think the original stuff works well when all pieces are functioning. Good luck.
Bill Haglan

Bill, - You might take another look at your radiator, as it may not be original. An original cell core radiator would be very difficult to "rod out", as it does not have smooth vertical fluid tubes. See here: http://mgaguru.com/mgtech/cooling/cool_100a.htm
There are precious few of these original cell core radiators still existence,although you can buy or build a new one (at a premium price).
Barney Gaylord

Mike,

You're welcome. For completeness, here's one more item for the list: Check that the spark plugs have the correct temperature range.

Dominic, did you confirm the temperature with an independent thermometer inserted through the radiator cap? It would seem that with an 82C thermostat and 72C gauge reading, one component or another was not working correctly. Either that, or it must have been very cold outside to run at 50C (122F)!

Steve
Steve K

Tom, for what it's worth, I chased an overheating problem for months. Mine would overheat at freeway speeds but was fine around town at lower speeds. I could drive all day around town but if I got on the freeway for more than 20 miles I'd overheat. It turned out that I had a very small leak in the radiator and I didn't detect it until I put a higher presure radiator cap on and bingo there it was, a tiny pinhole leak that under the demands of sustained 70mph driving reduced my Rad. capacity which caused boiling. I felt pretty dumb as I had denied any possibility of a radiator leak.
David Holmes

Dominic seems to have the coolest MGA around! My temperatures are fine at constant high speeds but at motorway speeds, i.e. in traffic queues, it boils and dumps all its water. Tried all the measures you chaps have mentioned, but still have to carry spare water against the threat of traffic queues.
Robert Divine

Yes I have verified the running temperature with a digtal thermometer. I suspect that most could address operating temps with a slightly richer moxture.

I was also puzzled by the fact that the car runs at temp below the thermostat rating, If it's below 15C when I drive, the car (with the Moss radiators) could never get to operating temperature unless I blocked off the rad.

In traffic it's still cool.

I suspect that the improved breathing from the supercharger has a lot to do with it.
dominic clancy

Barney

I checked out the radiator and it is an original. The guy at the shop who boiled it gave me a line and I didn't know any better. Oh well, that was 10 years ago and I have had no problems.

Bill
Bill Haglan

David, you may have said something that I overlooked. I have been seeing a very small amount of fluid in and around my radiator and engine but could not figure it out. I will remove the radiator and have it looked at.

I removed my "oil cooler" from infront of the radiator
and mounted it below the pan. The cooler fits great and
is't lower then the car. I used 1/4 in. bolts 3-1/2 in.long with 3 in. extenders cut from a 12 in. long pipe with a 1/4 in.I.D. I then inserted those pipes into a rubber hose for shock, cut them 1/8 to 1/4 in. longer and mounted it all to the same holes that were in the pan. I'm working on the horn placement this week.
Tom Peotter

This thread was discussed between 14/08/2007 and 20/08/2007

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