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MG MGB Technical - Add oil cooler to late MGB?

Hello all,
I searched (with no joy) through the archives for some information as to whether you can add an oil cooler to a rubber bumper B as those fitted to earlier cars.

I'm sure it's physically possible, but is it reasonably do-able?
Regards, David
David Steverson

I went the other way -- I deleted the oil cooler from my earlier car (1969). It's my belief that the oil cooler with modern oils probably does more harm than good -- modern oils don't have the coking problem that oils from the 1960s had, and oil that is too cool promotes accelerated engine wear. Oil that's too cool does not drive out contaminants as quickly as oil that comes up to proper operating temp quickly. (When an engine is started cold, unburned fuel washes past the rings -- fuel is a poor lubricant -- and water from combustion makes its way into the sump as well and reacts with combustion byproducts to form acid). Since removing my oil cooler and driving in hot temps, I've checked the temp of the sump with an infrared thermometer and found it's stayed around 180-190
Rob Edwards


only late 'MKIII' B's from 1974 1/2 to the end of 1975 were not fitted with an oil cooler (although the very first production MKI also missed it) but it can be added as used on the CB cars or as installed on late RB cars. You should buy new hoses and an additional oil thermostate and a new oil cooler if you think you need this 'upgrade', as old/used parts might be contaminated with dirt and might lead to problems with the bearings. Do not forget to also fit the rubber bushings to the holes in the radiater duct.

The installation is quite foreward as it only substitutes the steel pipe that is run from the end of the block to the the oil filter.
A more effective and better solution might be the use of a water cooled heat exchanger as used on different modern cars (Peugeot, Volvo, Citroen, VW). It is directly mounted to the oil filter adaptor and connected to the cooling circuit of the engine.


I wouldn't bother myself. I fitted a thermostat in the hoses to my oil cooler. The stat allowed oil to go through to the cooler if it got above 85 celcius. Except on the very hottest days, the stat never opened, which to me shows that if the cooler is always in circuit, the oil will never get hot enough to do its proper job.
Mike Howlett

Contact me via email and I can send you pictures of the oil cooler installation I did on my '79. It has definitely been an improvement during the hot Ohio summers we have had lately. Currently, the oil cooler is covered due to the lower fall temperatures we are having now.
Larry Youngblood

Hmmm, I never thought about the whole modern oil vs. 60's oil stuff. I just thought they were a good idea and dropped to save money in the last days of BL.

I'll send something from work here. It does get a bit warm here in Atlanta on the odd summer day. I'm just looking for ways to keep my B in good nick.

Thanks to all,
David Steverson


I agree with Mike.

If you do fit a cooler add a thermostat so you won't do more harm than good.

D M Tetlow

I just added one to my 78...the threads are pretapped into the front valance for the cooler itself and the hoses are easy to route and fit. I would cover the cooler for the winter months and agree that oil is supposed to be damn hot to do it's job right, but New York and the 90 degree summer days we get are a good enough reason for me to have fitted one to my car.

Relocating the oil cooler to a new position behind the front valance will provide unobstructed airflow to the radiator matrix, while mounting the vented front valance from the 1972 to 1974 ˝ models along with a venting duct to the oil cooler will, in turn, provide adequate airflow to the cooler. If you are going to install an oil cooler for the first time, use one that has at least 16 rows and install a 200 degrees Fahrenheit (93.3 degrees Celsius) thermostatic bypass valve, as overcooled oil can rob power and lead to accelerated wear. Because overcooled oil is thicker than it would be at normal operating temperatures, the piston rings will “hydroplane” over the oil and, on the upward stroke, scrape it into the combustion chamber where it will be burned, leading to carbon deposits and an increased risk of preignition. These units have a dual function in which the flow of oil is either channeled directly to the oil filter when the oil temperature is below 200 degrees Fahrenheit (93.3 degrees Celsius), or is channeled directly to the oil cooler when the oil temperature is above 200 degrees Fahrenheit (93.3 degrees Celsius). An excellent thermostatic bypass valve with the required ˝” NPT threads is available from Perma-Cool (Perma-Cool Part # 1070). Perma-Cool has a website that can be found at . Personally, I use Mobil 1 in all of my cars and I agree that it resists molecular shear better than the mineral-based oils. However, I prefer to think in the long-term. I use the oil cooler to help get rid of excess heat that can destroy the additives that were added by the refiner in order to help protect the engine. Just because the oil can stand the heat without rapidly breaking down does not mean that heat can thus be ignored. The crucial factor behind installing an oil cooler is the fact that it is the oil that carries away the heat from the moving parts. Engines last longer when their operating tolerances stay within engineering specifications, even when the oil is of the best quality. This being the case, I consider the oil cooler to be a wise move for a car that is going to be kept and run for many years.
Steve S.

Thanks Steve. I've seen a thermostat recommended several times, but I hadn't seen a source till now.

C R Huff

Glad to help. There's nothing like complete information, eh?
Steve S.

Right you are, Steve. I copied and pasted the info for later use.


C R Huff

This thread was discussed between 19/10/2008 and 30/10/2008

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