navigation bar

Exploding Waterpumps?

by Greg Fletcher


Water pumps on the Jensen Healey are not all alike, the key is the two-piece seal. I was told that the two piece seal was originally designed by a former partner of Dave Bean of Dave Bean Engineering, now in San Andreas, CA. Dave Bean now owns the rights to the seal which is put together from a rubber seal & carbon disc mated to a thin ceramic piece having a rubber seal on its back. These two-piece seals tend to last longer and keep water away from the bearing. The old style one piece seal can, under the right circumstances, cause catastrophic failure when the unit seizes, even causing the pump to explode- so while this is not common at all, I have talked to two persons that this did happen to! Dave Bean, Delta MotorSports and Bruce Madden all deal with the two piece seal kits.

New water pumps can be had for about $450. Not a great value. It's hard to image that they would last any longer than a proper rebuild. New Lotus pumps used to be the one-piece seal, I haven't talked to anyone that really knows for sure if they have been improved or not.

Seal kits now run about $73 but you'll need a press and some basic knowledge of the specifications or at least know of a shop that you trust to do it. I've also heard more than a few times about people getting their pump back with a cracked housing from dubious operators. Core charges for that old water pump range from $50 to $100.

Delta has a rebuild exchange thing going on for $135. Send in your old rebuildable pump and get the core charge refunded. This route is fairly painless and youčre back on the road in no time.

Unfortunately for me, the day I called was an unusual time, when Delta was out of stock and a week away from getting their shipment of rebuilds in. In my hast, I decided to bypass attempting to rebuild my old pump myself (a job for another day) and instead send away for a rebuild from Jensen guru Bruce Madden in Atlanta, Georgia. Besides being certifiable (he is reputed to own 21 Jensen Healeys) Bruce has done a lot to further the Jensen Healey cause; original promoter of the rubber camshaft cover gaskets, safe 907 water pumps and rebuilder of numerous other hard to find J-H parts. He does this in his spare time so he's not always sitting by the phone, but will always get back to you if you leave a message. In my case he was able to send out a rebuilt right away, $132 less core charge.

Some good tips to keep that pump working for a long time: Use a 50/50 mix of quality coolant and distilled water, use a can of Prestone Water Pump Lubricant (or similar product) to help keep seals in good shape and don't use any flex water hose with wire in it (it rusts over time and thrashes the delicate inner wrkings of your pump).

main | jensen | techpeople & places | marketplace | message board | join | garage | links | mail