Lotus K series engine



TEL: (03) 9372 3111, FAX: (03) 9372 3122

ACN: 006 798 492 ABN: 74 006 798 492




January 2008


This engine was fitted to an MGF that had an original 40,000 kms on the clock. Coolant had contaminated the engine oil and the removal of the sump pan revealed a stain indicating a leaking sleeve seal.

The engine was pulled and stripped down. The offending sleeve had stains between the block and the sleeve which is evidence of the sleeve glue/sealant having failed.

The engine was rebuilt, fitted and road tested before handing over to the owner.

It came back with the same problem within the week.

The engine was stripped again and the same sleeve was again leaking.


On closer inspection of the block we found a local area of casting porosity across the sleeve sealing shoulder in the block. The anomaly extended over a section the size of a 50 cent piece. It was not practical to weld, the casting sealing factory was not able to do the work in the time frame we had available, and so we sealed it using Loctite 7649 pre-cleaner and their 515 flange sealant followed by a pill in the radiator.

The engine was refitted and handed back to the owner.

The vehicle failed again some two weeks later and this time given to the dealer to sort out. Fortunately the dealer uses us also and we were asked to advise.

Cause of this third problem:

Unlike the first and second failures, this time the engine oil was totally free of coolant contamination. Instead, the head gasket was leaking but not until after the radiator temperature went way beyond normal.

Having had so much trouble with the engine, we went over the total installation with the dealer.

The radiator has a twelve tube construction and seven were found to be totally blocked. Certainly this was the main problem and it had been overlooked by the engine installer as he believed that a 40,000kms vehicle would not need the radiator to be checked. (The owner had been using sealants before bringing the car to our mechanic). We were also able to establish that the installer did not have the adaptor in his pressure tester to test his installation.

Note also that the dealer warned that the water pump on this model has had pump impellers spin on their shafts. This check was made and ours was OK.

The sleeve installation procedure specifies that only the genuine coolant be used as this was compatible with the sleeve sealant. Apparently some aren’t.


We will be pressure testing any assembled K series engine in future. The installing mechanic has purchased the adaptor for pressure testing the vehicle. We will also be advising the installer to use only genuine coolant in this application.