MG-Cars.info

Welcome to our Site for MG, Triumph and Austin-Healey Car Information.

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG MGB GT V8 Factory Originals Technical - Rover water pump leaks

My 3.5 has started weeping coolant around the long-bolt heads that go through the timing cover into the block (4 of them to be exact but only weeping around 3).

Any one ever had this happen to them?

This problem started out as what I thought was a small leak in my rad. Had that tested by the guys that built it with no problems. I put it all back together, pressure-tested the system before start-up and sure enough, coolant was leaking around the bolt heads. I've since swapped the gasket, new sealant but the leaks are still there.

Not much in the archives other than to use "anti-seize" on the threads. I thought I'd read/heard that the bolts enter the water jackets but from what I've determined, this doesn't appear to be the case.

The only thing I can think of is a bad gasket/sealant between the pump body and the timing cover and the coolant seeping into the bolt holes.

Any ideas or suggestions greatly appreciated. The car has done 2500 miles this past summer with no problems so don't know why this has started now.

Thanks!
Simon
Simon Austin

Simon:
I had the same problem with one of these bolts (top one on driver's side) on initial startup of my new engine a few weeks ago. I removed and cleaned the bolt and re-installed it with a liberal amount of ARP thread sealer. I have run the engine once since with no apparent leak.
Good luck!
Phil
Phil O

I use silicon sealant, same deal.
"Ultragrey" blends in nicely
Peter

Thanks gents. I'll give it a try.

Cheers
Simon
Simon Austin

Just before this thread disappears into the archives, thought I'd update the leaking problem.

Pulled the bolts out again, cleaned them and applied Permatex Thread Sealer as Phil mentioned New gasket and sealant applied. Pressure checked the system and looked good. Didn't run the engine at that time. Had a look at the bolts a few day later and what do my wondering eyes see............ a small drip under one of the bolts!!

I know these things are British and have a passion for leaking but this is ridiculous. Checked all the bolts for tightness which seemed to help a bit.

Close examination with the pump off indicates the bolts don't go through the water jackets but above and below them so the only place coolant could get into the bolt shafts would be at the "joins" between the pump body and the timing cover and the the cover and the block.
Leaks aren't quite as bad when first started but really occur when at or above operating temperature (when pressure is greatest, of course).

Is this a problem unique to Rover engines or do owners of BOP units have this problem as well?

Simon Austin


Sounds like a uniquely Canadian problem. Seriously, it's never been a problem on my Buick motor (which I've been running almost 14 years). Could it be that your bolts are a little too long? (or at least their unthreaded sections...) Perhaps they bottomed-out without squashing the gasket. You do have hardened flat washers under the bolt heads, don't you?
Curtis

Lots of silicon and wipe off excess.
My front cover is a range rover one but I seem to recall there is a possibility of a leak into the bolt housing, thence out around the head. Is the shaft of the bolt rusty?. Likely the case if so.
Could also be that you've got a crack in the pump itself and a drip is running down and hanging off that bolt.
Peter

Good points, guys.

Curtis- funny you should mention about the flat washers. I didn't have any before but do now but still have the leaks. I had a look at a Triumph Stag today with the Rover conversion and noticed it had smaller diameter but thicker flat washers in addition to lock washers. Might give that a try. Thought about the "too-long" bolts as well but compared them to the ones showing in the Rimmer Bros. catalogue (3 x 4.5" and 1 x 5.5") and they seem correct. The use of the thicker flat washer may make the difference.

Peter - no rust but the top bolt on the driver's side (LHD) was wet the first time I took it out. Now, ironically, it's the only one not leaking.

My engine builder hasn't heard of this problem but did suggest silicon sealant around the washers and then tighten them.

Thanks for the ideas!
Simon Austin


I'm not a believer in silicon sealant on bolts... seems to me it's just a "band-aid", and that the real problem is (for some reason) your gasket isn't doing it's job. Have you tried replacing it? Once a gasket has leaked for awhile, it's probably ready to be thrown away and replaced.

Flat washers help bolts do their job. With them, you can get a more true torque reading initially and you're less likely to lose torque (or actually tension) in the bolt over time. You're also less likely to damage the casting.

Split-type (spring) lock washers, by the way, don't and can't work. As Carroll Smith explained (paraphrased):
"It takes very little load to compress a spring washer. The spring washer will be completely flattened long before you reach recommended torque. Once compressed, the spring washer is nothing but a flat washer. If your bolt loosens to the point where the lockwasher opens enough to become a spring, there won't be enough residual tension in the bolt for it to function as designed anyway."

If you must apply sealant, make sure you apply it to perfectly clean surfaces. I don't know how you're going to manage perfectly clean bolts and still use anti-seize.

Curtis

Hi Simon

It must be a Rover 3.5 Canadian thing. It happened to me as well. I cleaned the bolt made sure I had the thicker washers and applied silicon.

Bruce
Bruce Mills

Maybe it is a Canadian thing. This is the first winter for the car and it may have taken a disliking to the conditions.

Curtis, that was a thought I had about the gasket not sealing properly between the pump and timing cover but I did install a new one. Fairly thick one that came with the gasket set for the engine.

Those flat washers I mentioned seeing on the Triumph Stag were the only washers on the bolts. We may be on to something here. The Rimmer Bros. catalogue doesn't show lock washers either, just the thick flat ones.

Bruce - did you have leaking on more than one bolt?
Simon Austin

Simon

I only remember having trouble with the top bolt. Same as Phil.
Bruce Mills

This thread was discussed between 05/12/2005 and 17/12/2005

MG MGB GT V8 Factory Originals Technical index

This thread is from the archives. Join the live MG MGB GT V8 Factory Originals Technical BBS now