why oh why is my new water pump still leaking

Someone help me please I'm really starting to lose faith in my car.

I've fitted a new water pump and I'm getting drippings.

I rubbed the mounting face down and degreased it, O ring is in and even used a bit of RTV sealant too.

All 4 bolt torqued up nicely, all 3 hoses in place and tightened up.

Thermostat is in with O ring and elbow seemed to bolt up ok

I've only got 1 litre of fluid in the system and its dripping out fast, as the amount in the car is so low it suggests that is the lower end of the pump I.e hose inlets or elbow.

Water looks to be coming from behind the elbow so it could well be from between the pump and the block as this is directly above it.

If I've done everything right why is this happening

Do you have the plastic t-stat cover?  
replace it.

when you replaced the pump did you remove the housing on the car, and fail to clean/sand the mating surface?
Did you torque the housing bolts down to proper torque.

I found that for piece of mind, that when I had the plastic t-stat covers I replaced them out of hand when changing the t-stat or draining the system….

Once I found the proper metal covers, I replaced them all, and haven't has an outlet failure since.

Gosh I really despise/hate plastic parts.

Oh, and I found that some vendors of replacement o-rings to be a tad smaller….

Briano1234 pump and housing all as one part and properly sanded and degreased the mounting face and the 2 points for the other bolts too.

When you say about the O ring being smaller do you mean in thickness because I did think the ring was a little shallow once in the pump

And yes plastic T-stat elbow, I've heard they can warp but I thought were obsolete parts now?
Mine appeared to be ok but unless it was lined up next to a brand new one it would be hard to tell.

Im getting a bit tired of watching new coolant running down my driveway. Is there an alloy alternative? 

On my Cabbies there were metal ones offered, and I quickly bought 2 of them I think they were 30usd apiece,  pssst don't tell my wife…I mentioned that in one of the forums, and they sold out of their stock in 2 weeks….

I had noticed that one of my local vendors o-rings were different, and wouldn't hold the t-stat in place, thinner…
so I would suspect o-ring failure over anything else unless your housing is cracked.

May have to see if something can be made up for the elbow in the meantime I think I'll be using a silicone sealant on it 

photos   help as i am confused with elbow

installed wp

Elbow as in the T-stat housing plastic joint. 
May have to get some RTV on it and let it seal itself if possible 

Don't loose faith mate, it's the joys of a classic and you'll feel good again when you get it sorted and can enjoy the car again!
AFAIK earlier engines had alloy coolant flanges on the head and for the thermostat housing. My 1983 1.8 GTI has alloy. Keep an eye on eBay etc for an alloy one or post a wanted ad on here. There was one not long ago and I had it saved in my eBay watch list for quite a while for £20 but it seems to be gone now.
When I fitted my water pump, the new pump came with a few different O-rings but the one I used fitted in the recess quite snuggly and held itself in place but also protruded quite a bit so it was very tight against the block. I also gave the mating serface on the a very good clean and also polished it with some fine grade wet & dry and wd40. I also greased up the bolts with copper grease before installing.
Just out of interest, did you replace the water pump and body or just the pump itself? If you look at Briano's picture his pump is brand new and shiny but the body with the hoses is older looking. I replace the lot on mine because I snapped a thermostat bolt off when I was replacing the stat.

Saulty same procedure mate, full pump and housing change, all bolts copper slipped.

Im thinking the O ring isnt thick enough to do the job.
Looks like its all coming off . . . again 

Before you strip it all back off, just double check that the radiator hose onto the thermostat housing is tight enough. I stripped mine all back down again because I thought it hadn't sealed and it was the bottom radiator hose. Also might leak if you have the jubilee clip too close to the flared part of the stub on the thermostat housing. May not be it but worth trying before you remove everything.

first thing I would do is to get a new t-stat cover and gasket.

Then I would replace the lower radiator hose.

Yes I re-used my housing, as I take my housings out to change the water pump,,,, I soak the bolt from the rear with pb-blaster then I use an electric impact to remove the bolts, If they snap I can drill them out, but soaking them apply a tad of heat, and an impact, and I haven't had to replace a housing yet. going back I use never-seize on the bolts and torque them to 87 in/lbs….

I decided not to clean the outer on that one, but the other cars is nice and shiny….

Right tried to tighten the inlet elbow bolts as they weren't overly tight and one sheared off as soon as I looked at it.
Got it out now so going to try to source a new inlet elbow and some thinker O rings for piece of mind.
The ones supplied are 50mm I.d x 3.55mm.  I'm thinking 4mm or slightly thicker will be better 

I have a spare alloy elbow if needed

Thanks for your help everyone.
A new T-stat housing has cured the bottom end of the pump leaking issue and fitting a 4mm O-ring has cured the issues at the top 

Hi, just doing the same job and snapped one of the 10mm housing bolts. Does anyone happen to know the length of the t/stat elbow bolts so i can buy replacements?

 

I hate to say this but it is better for you to replace the housing at this time, as well as the water pump, you can get both as an assembly and it isn't that costly.

The reason I am saying this to you is that if the t-stat cover bolt snapped, others will when you have to replace the water pump and you might as well do it right so you won't have to be down another day or three in the future, I would also source a new t-stat cover as well.

I have a how to change it in the archives section just click the link in my signature.  If you don't have a/c or p/s then it is a whole lot easier.

View topic: My DIY list of things for a 90ish Cabriolet (digifant2) part 1 - The Mk1 Golf Owners Club

And be sure that you remove all the new WP bolts and either wrap them with teflon tape, or Copper grease, and make sure that you only torque them to 87 in/lbs  other wise you will strip the threads in the housing.

Sorry i missed some info. I am replacing the whole water pump unit.

I have a new thermostat elbow but i discovered the existing is metal so i'm inclined to clean that up and refit that to the new water pump.

So i was just looking for the lenght of the 2 bolts that mount the elbow to the WP. I think they're M6 x 20mm.

Briano1234   do you mean to remove and copper grease the 4 bolts that mount the WP to the block or are you saying to remove the brand new bolts from the WP that hold the 2 sections together and refit??

 

ah....m6X22