Water pump GRAF or GMB

Currently running a fvp, which is just a gmb, and it works great.

Graf here. 15k miles/ 2 years, no problems.

I use on my 12v and 24v VR6 engines, Eurowise aluminum thermostat housing and 42DD stainless steel crack pipe. Water pump I use GRAF or Hepu for its metal impeller.

I've been running the aluminum GMB pump (1301280AL on Rockauto) on the 455 in my '72 Bonneville for about 5 years now with no problems.

I have 20-25k miles on a GMB pump now and it hasn't leaked a drop. We'll see how long it goes, but so far I'm happy with it.

If it *is* leaking you might want to consider replacing it with a Graf alloy-bodied pump which won’t be affected by heat and exposure to oil, the usual causes of eventual failure of the plastic pumps.

I've also had a Graf I think it was, it did have a metal impeller, which started leaking after 7 yrs.

what I had problems with is with Graf water pump, that was included as part of FCP euro cooling system kit, water pump seal around the bearing started pouring coolant like a waterfall after only 11k miles, I replaced it with a Stewart pump

the metal fins are spot welded like shit on these cheap metal waterpumps. my graf pump also started to leak from the weep hole after a year too

Have had bad luck with graf metal impeller pumps, multiple failures over 2 different cars.