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MG MGB Technical - replacing/deleting oil cooler

I appears as though I must remove the front bumper to access the oil cooler to correct a leak. Is their an easier way? Can I bypass the cooler by rinning one hose to both block connections?
Thanks
Tim Brazil

Tim-
Yes, you can completely bypass the oil cooler by simply running a hose from the block to the oil filter stand. I don't recommend it, though, as your oil is part of the cooling system. Some people will get on this thread and point out how the late model MGBs had no oil cooler. However, you must bear in mind that these engines had their power output chopped in an attempt to meet EPA standards. Power = Heat. If you have ambitions of increasing power output, then an oil cooler is a smart thing to have. What year is your B?
Steve S.

Steve,

Just added a 13 row cooler with a thermostat yesterday. Should it be unbolted and proped up to drain when the oil is changed, or, with frequent change of Mobil 1, would it not matter?

rn
RN Lipow

RN-
With frequent changes of both Mobil 1 (@ 3,000 miles) and a good oil filter such as the K&N Performance Gold (Part #HP 2004) I would think that there would be no real need to drain the Oil Cooler. Mobil 1 is a high detergent synthetic oil which will keep particulates in suspension quite well, allowing the oil filter to remove them. It also doesn't form sludge or varnish, so the Oil Cooler will stay clear and flow efficiently. The oil is so good that the small amount of old oil in the Oil Cooler and its hoses shouldn't really matter. It's only when the owner uses El Cheapo oil filters and El Crapo oil that he needs to worry about such factors. Of course, if he's doing such things, then he won't. On the other hand, anybody who would install a nice, clean new Oil Cooler and use Mobil 1 plus a good filter does wonder about these factors, but doesn't need to. Funny how that works out.
Steve S.

This subject has been covered extensively in the past and should available in the archives. Roger Parker, who is rather knowledgable about these things, suggests that the oil cooler was not used on most applications of the B series engine, including some of equal heat rasing potential. He further suggests that an oil cooler, if used, should be set up with the "thermostat" between the two lines so the oil is bypassing the cooler until it is warmed up. Remember the old "most engine wear occurs during start up". The quicker the oil is up to operating temperature, the better the engine is protected. An oil line thermostat, when an oil cooler is fitted, is highly recommended. As to the protection the oil cooler provides, the cooler split on my 68GT, right below where the line goes into the cooler. Removed the lines and cooler, ran a bypass hose and took it for a test drive. Engine shows no different operating temps than it did with the oil cooler in place. Could this mean that the DB oil cooler, placed in front of the engine radiator, is blocking air flow to the radiator in proportion to the amount of cooling it is supplying to the oil? Do not know, but, in two years testing, no differences have been shown between running with and without a cooler. As to unbolting the oil cooler when draining the oil. On the RB cars, this is rather impractical as the oil cooler sets below the valance, but it no longer blocks the radiator in that position. With the CB cars, the cooler does sit on top of the platform, but the hoses go through the radiator support and that has to be removed to elevate the cooler and lines to drain. Seems like a great deal of work. You might try running a bypass line and see what happens. I did and it has worked well. Also cuts in half the number of oil lines that can fail. Les
Les Bengtson

Thanks for the info, Les. I've been considering adding an oil cooler to my '78 - thinking that it might extend the life of the engine. Now, I probably won't (unless someone does a pretty good job of convincing me that it's necessary). Especially considering your recent oil hose problem!
My '78 runs cool anyway. The air pump, cat converter, etc., have been removed. It never gets hot even in 95* temps in traffic - and one of the twin fans doesn't work! The car isn't driven hard - normal use is just for a little gray-haired couple to cruise the back roads on nice days :-)
I will probably go on and replace the twin fans with a single large fan. Besides, it's cheaper than a new oil cooler kit..
Joe Reed

A similar thread a few weeks back asked the same question. As I mentioned
then I removed my oil cooler over two years ago and have not noted any oil
pressure or engine temperature differences. As Les stated less lines and no
cooler presents fewer places for a leak to occur. FWIW Clifton
Clifton Gordon

Thanks all. Its mounted in front of the radiator just in front of the aftermarket electric fan. I installed the thermostat for the bypass when cold and noticed no change in engine (radiator) cooling

again, thanks for the responses.

rn
RN Lipow

Les, Joe, & Clifton-

The fact that the gauge displaying engine coolant temperature remains at a reasonably normal temperature reading can often be misleading. We once loaded up a friends Caprice Classic and took off on a trip that required us to cross over the Blue Ridge Mountains. It was a hot day (about F95), the trunk was loaded, and we had six people in the car. When we got to the top of the mountain we pulled over into a Lookout to enjoy the view of the Shenandoah Valley. Out of curiosity I checked the oil and despite the fact that the temperature gauge read "Normal", found that the oil was as thin as water! It sure was a good thing that we'd stopped!

Many races on the track are lost due to lubrication failure. As a result, many track racers install a separate gauge to monitor the temperature of the oil because they've learned the hard way that the engine coolant can be at an acceptable temperature while the oil is being fried. I have one in the dashboard of my car. On a bone-stock MGB the gauge would be a frivolous luxury. On a power-enhanced engine that gets driven hard, it's a good idea. An Oil Cooler is definitely a smart thing to have.
Steve S.

Gentleman;
Not to mention as frugural as our BMC friends were do you think they would have added a cooler to a B if it were not called for??? Not there style! Bob T
Bob Thompson

I only know this...on my new engine I had good oil pressure without a cooler (as you would with a new build). I did, however, notice a bit of fluctuation at different running temps and a lower idle pressure after hard runs (albeit, still at 40 lbs, which is excellent). When I added a cooler (which I had before and probably allowed me to run the old engine longer), my oil gauge never dropped below 50 lbs and has much less fluctuation. Typical running pressure is 75 lbs with very little fluctuation. Just where she ought to be on a healthy new engine with only 10K or so miles (using a normal oil pressure relief spring). This is my own experience...I have no idea why it improved with a cooler nor whether this would be the case for others. I find myself wondering if the pressure is simply steadier with a higher volume. Hard to say, but I like the results.

Barry
Barry Kindig

Barry-
The explanation for what you experienced is easy: The hotter a petroleum-based oil gets, the thinner it becomes. The thinner the oil, the lower the pressure. Anybody who doubts this need only refill their sump with straight 10W oil and check the pressure gauge when it the engine reaches operating temperature (if they dare).
Steve S.

Not to start a rash of replies but..Over several years and several aircooled VWs, I have noticed (and heard confirmation thru other owners) that synthetic oil is more designed to lubricate than to cool. It is not the best for engines that must rely on oil to carry away heat. I once worked on a blimp (virgin Lightships) and they had modified VW type engines. Their mechanic told me the same. He was strict about never using a synthetic due to the higher temps that the engine would run.
kids1

Thannks for the comments regarding delieting the oil cooler on my 75 mgb. I bypassed the cooler this evening, started it up and heard a knocking from the engine, as if low oil pressure. This occured immediately after starting it, when it was cool. I am ordering a new oil cooler to install, and hoping this eliminates the knock.
Tim
Tim Brazil

This thread was discussed between 09/03/2002 and 13/03/2002

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