Can a wrong-rotating water pump cause strange cooling issues?

[chepsk8]

Trying to sort out a cooling system problem in my Factory Five Cobra.

Stock 5.0 & Mustang radiator, longer hoses (Mostly metal to avoid hose collapse), and a replaced water pump.

Car does not leak, but will lose coolant & overheat, takes longer when I put on a 20lb cap. Cooling system pressure check holds pressure, drops very slightly over time. Compression on the motor is good, and it does not increase cooling system pressure when running (as far as I can tell).

So, I am trying to eliminate all problems, down to either a head gasket or bad water pump. Coolant flow is in the right direction, but lots of air in the system, can't get a good fill.

So, what's your take? Wrong rotationg water pump? Head Gasket? I'm stumped.

Thansk for your usual great help!

 

[Hef5.0weisen]

i was thining water pump also a while back, took me forever to convince myself a HG was popped. sure enough, blown HG. no oil in water, vice versa, no steam water in tailpipes, comp test was fine, car ran great, boost gauge didn't flicker at all, jusy o'heated. HG had a 1mm wide split from one of the bores to a steam relief hole(?), sure enough compression was entering th e coolant their, pushing all the water out. I say HG, good luck
this is assuming you've done a bunch of other troubleshooting...ie verified actual temps, bled system etc.

 

[chepsk8]

My thoughts as well

Yes, I'm thinking that too.

I'll probably pull the heads in a few weeks. Curiosity, which cylinder was in trouble on yours? I am suspectinf pass front cylinder, as that has the lowerst compression, and is next to the water jackets.

 

[Hef5.0weisen]

mine was #2 and #3, both had the split. hope you get it goin

 

[ROLLIN5.0]

Definately HG building pressure in cooling system, blowing coolant out the overflow when the engine is under a load. The higher pressure cap you run, the longer it will take to lose it, but it just adds more pressure too. Try running your radiator cap only on halfway. It will still lose coolant under load, but it will not build pressure, so under normal driving conditions, it should take longer to lose it, plus you won't be putting all that pressure on everything else in the system. It worked for me on a past SC'd application. With the cap all the way down, I would be hot within a few miles of running boost. With it only on halfway, I could drive 200+ miles.
Brandon