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neckstrap · 05-07-2007, 04:38 PM

When I built my Cobra replica (1986), I put an oil cooler in the nose. I used aircraft quality hoses from the engine to the cooler and from the cooler to a double remote oil filter and from the oil filter back to the engine. I drove the car for probably 4 years that way and had a lot of problems with leaks and hoses splitting near the connectors. I think that rubber hoses are pushed to their limit carrying oil at engine temperatures and pressures. I decided that the oil cooler was not that important and having a reliable car was. So, I scrapped all that stuff and went back to a stock spin-on filter on the block. I have driven the car for ten years since then with no more problems.

The big question is, does the Lotus NEED the extra cooling? Engine oil should run at over 175 degrees F to lubricate property and evaporate any condensed water. I suspect that the double Lotus oil coolers keep the oil below that, except in really hot weather or on a race track. I believe that most of us would be a lot better off without them. Guys who build high performance engines for racing applications use a thermostatic valve to bypass external oil coolers until the oil has reached the proper temperature. Then, the valve diverts the oil trough the cooler as necessary to keep it under 230 Degrees. I don't find any thermostatic control on the lotus and that means that the oil may never reach the best temperature unless you live in Phoenix. Most of us would probably avoid a lot of leakage problems and have better lubrication and SAVE A LOT OF WEIGHT by removing the oil coolers and using the stock Toyota oil system.

The proof would be if someone installed an oil temperature gauge on their Lotus and tried running with and without the oil coolers. Since mine is not even running yet, I can't try this. Any volunteers?

Paul

05-07-2007, 04:38 PM	#9 (permalink)
neckstrap Registered User Join Date: Feb 2007 Location: Northridge, California Posts: 177 Images: 4	I have had a number of problems with a similar set up. When I built my Cobra replica (1986), I put an oil cooler in the nose. I used aircraft quality hoses from the engine to the cooler and from the cooler to a double remote oil filter and from the oil filter back to the engine. I drove the car for probably 4 years that way and had a lot of problems with leaks and hoses splitting near the connectors. I think that rubber hoses are pushed to their limit carrying oil at engine temperatures and pressures. I decided that the oil cooler was not that important and having a reliable car was. So, I scrapped all that stuff and went back to a stock spin-on filter on the block. I have driven the car for ten years since then with no more problems. The big question is, does the Lotus NEED the extra cooling? Engine oil should run at over 175 degrees F to lubricate property and evaporate any condensed water. I suspect that the double Lotus oil coolers keep the oil below that, except in really hot weather or on a race track. I believe that most of us would be a lot better off without them. Guys who build high performance engines for racing applications use a thermostatic valve to bypass external oil coolers until the oil has reached the proper temperature. Then, the valve diverts the oil trough the cooler as necessary to keep it under 230 Degrees. I don't find any thermostatic control on the lotus and that means that the oil may never reach the best temperature unless you live in Phoenix. Most of us would probably avoid a lot of leakage problems and have better lubrication and SAVE A LOT OF WEIGHT by removing the oil coolers and using the stock Toyota oil system. The proof would be if someone installed an oil temperature gauge on their Lotus and tried running with and without the oil coolers. Since mine is not even running yet, I can't try this. Any volunteers? Paul Last edited by neckstrap : 05-07-2007 at 05:24 PM.