Cooling a 231 V-6 conversion

Re-printed from the Club’s newletter and only sent to club members


A rebuilt 231 odd-fire V-6 was newly installed into a member’s Jeepster. The installation went well and the motor fired up on the first try. After the break-in period, it was determined that this new engine was burning a quart of oil every 150 miles, so it was again yanked out and rebuilt once more by the builder.

After reinstalling, the motor seemed not to burn oil. However, a problem occurred that was warned about, but paid no heed to, that being, the motor ran extremely HOT! Even on a cold rainy day. When driving around town the temperature would run around 200 degrees but at freeway speeds it would climb up to 230 degrees plus! Not good.

A 2,200 cfm electric auxiliary fan was installed in the front of the radiator in hopes that this would solve the problem. It did not.

Talking to other members who have already installed the 231 V-6 motors, it was concluded that a radiator with more water capacity was needed. Several members put a “4-row” radiator in and have had good results so it was decided to do the same. A reputable radiator shop was selected, one that deals with Jeeps, to install a high efficiency desert 4 row radiator in. The 4-row radiator core actually used the original Jeepster’s upper and lower tanks and side straps, thus making this conversion a simple bolt in.

The shop’s owner said they actually had a better radiator for freeway speeds, but it would not be as effective while 4-wheeling because it had more “fins” per square inch and this could lead to low speed heating problems. He did recommend installing a shroud which helps cooling efficiency when under 40 mph. This is going to wait since I have an electric auxiliary fan.

Did it work? YES. While pulling a dangerously over-loaded 5×8 enclosed trailer over long steep grades, the temperature gauge never went past 180 degrees. The weather conditions were clear and the temperature was between 60\65 degrees. Compare the above to this; Rainy weather with a temp. of 55 degrees, traveling on a slight incline at 60mph with no trailer and the temperature gauge shooting up to 230 degrees plus. The motor now runs about 22% cooler then it did with the stock radiator.

It was worth every penny it cost and highly advised to anyone who wants to install a 231 V-6 or small V-8 engine in their Jeepster. It is recommended that you install the high cfm auxiliary electric fan as well. This should help out at lower speeds on 100 degree plus days.