You are here:

MG Car Repair/MG Oli filters One way valve


Thank you Barrie for solving a mystery!- my 74 MGB oil gauge usually takes a few seconds to register pressure and this always caused me to wonder why, but I assumed a sticky gauge. Other times it showed pressure immediately, which now I know meant I had installed the correct filter.   

Q: how do I know the filter has a one way valve? can you see it upon inspection? I have never heard this mentioned on any other blog.
thanks Paul

Sorry for the delay, I just moved house.

If there is a long delay between starting a cold engine and a reading on the oil pressure gauge, then it is probable that the system is draining due to the lack of a non-return valve inside the oil filter element.  I always buy my oil filters from a reputable supplier such as Moss.

MG Car Repair

All Answers

Answers by Expert:

Ask Experts


Barrie Jones


MG Sports Cars from 1949 to 1980 - Including MGB, MGBGT V8, TF1500, TF, TD and modern Midgets. I also specialise in SU carburettors, Lucas wiring, suspension, steering & brakes.


I have owned my 1955 TF1500 since 1966. Technical specialist for the TD and TF with the MG Car Club T Register. Also owned 20 MGBs and currently own an MGBGT V8. Written 3 books on MGs and produced a DVD on how to strip and rebuild the TD/TF gearbox.

MG Car Club.

Barrie's Notes on the 1953-55 MG TF (author). /=====/ Barrie's Notes on the MGB (author). /=====/ Barrie's Notes on the MGB GT V8 (author). /=====/ The Essential Buyer's Guide to the MG TD, TF and TF1500. (author)

M Phil, C Eng, BSc (Eng).

©2017 All rights reserved.