Detroit Diesel — Replace Water Seal (Water Pump)
Repair & overhaul
From a Detroit Diesel service manual — check it applies to your exact model before use.
Before you start
- A new ceramic impeller insert must be used if the seals were removed.
Procedure
- Remove the pump cover and gasket. Remove the locknut and washer and withdraw the impeller with puller J 24420-A.
- Grasp the water seal assembly with suitable pliers and pull the seal out of the retainer.
- Apply a light coat of non-hardening sealant to the outside diameter of a new water seal. Tap the seal into the seal cavity with a suitable sleeve resting on the brass cartridge lip.
- Inspect the impeller for wear (erosion). If reused, replace the ceramic impeller insert by baking at 500 F for 90 minutes and cleaning the insert area, then bond a new insert with adhesive washers and
- Make sure mating surfaces of the water seal and ceramic insert are free of dirt, metal particles and oil film.
- Apply International Compound No. 2 to the pump shaft threads. Place the impeller and washer on the shaft and start a new lock washer. Hold the pump gear and draw the impeller down with the locknut; ti
- Use a new gasket and install the water pump cover; tighten the nuts securely.
Tools required
- Puller J 24420-A Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Impeller-to-shaft locknut 35-40 Amazon eBay FridayParts $46.99 lb-ft (47-54 N*m)
- Ceramic insert bake 500 F (260 C) for 90 minutes
- Cure impeller assembly 350 F for one hour
Source: Detroit Diesel service manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.