Prole Posted December 8, 2019 Report Share Posted December 8, 2019 Like above rebuilt my gti block recently and getting the coolant level dropping and air getting in the system, causing a overheat issue. Done everything on the motor all new, a friend said did I seal the water pump. As in the use of gasket sealant as a precaution. Could it be a dud water pump or could I have a crack on that area of the block? This block had a simular issue before being rebuilt but that was head and a cam cover being gone and air or exhaust gasses getting in the coolant. Quote Link to comment Share on other sites More sharing options...
Rich Posted December 8, 2019 Report Share Posted December 8, 2019 Sounds like you need to do a leak down test whilst watching the levels. Quote Link to comment Share on other sites More sharing options...
LR5V Posted December 8, 2019 Report Share Posted December 8, 2019 Is it physically leaking? -pools of coolant under the car? I rebuilt my front end, mine kept drinking coolant, thought head gasket was away. On initial fill I did not measure how much I put in, no point as I had a different radiator, but I added at least 5 litres on top of the initial fill - Turns out it was all good - I had put mine together on a sloping drive - very sure it was trapped air. Quote Link to comment Share on other sites More sharing options...
Prole Posted December 8, 2019 Author Report Share Posted December 8, 2019 20 minutes ago, LR5V said: Is it physically leaking? -pools of coolant under the car? Yep a small leak, noticed coolant on the bottom of the sump (not on the ground), but the coolant line going to the oil cooler/heater was slightly perished and squirting coolant (when pressurised) about so assumed it was that, I've changed the clamp to a torque clamp (think that sorted it, but maybe not) But it was the garage told me it was around the water pump when I went for the MOT. The expansion tank is draining pretty quick, but that's a mixture of air getting in and coolant loss way more noticeable after a drive when it's pressurised. I put it down to like you said an air lock, but not to sure now. 28 minutes ago, LR5V said: I had put mine together on a sloping drive - very sure it was trapped air. An thought the same at first, an I too built on a sloped drive . Lower rad hose wasn't getting hot and also with the out from the heater matrix so pumped it though and is heating up as it should. An on another note, when building my radiator fan died, blown fuse (changed it) and then got my other radiator temp sensor an got a lighter to it an the motor had gone. Had a spare fan tested that all good. But now got a feeling my other fan has also bit the bullet. Is there anything that may cause this as the fuse is fine. Quote Link to comment Share on other sites More sharing options...
Rich Posted December 8, 2019 Report Share Posted December 8, 2019 Slack head bolts? Quote Link to comment Share on other sites More sharing options...
LR5V Posted December 9, 2019 Report Share Posted December 9, 2019 I would want to find exactly where it’s coming from - timing belt side suggests poor fitment/sealing On the other side There is the pipe from the back of the pump - the one that goes all the way to the gearbox side of the engine - is that new? Fully pressed home? Quote Link to comment Share on other sites More sharing options...
Prole Posted December 9, 2019 Author Report Share Posted December 9, 2019 7 hours ago, Rich said: Slack head bolts? All done to spec and then tested torque over the whole head finding the tightest bolt and tightened the slightly slack ones to about the same torque setting. Head was skimmed, crack tested and the block was tested flat an prepped properly. 7 hours ago, LR5V said: pipe from the back of the pump Using oe pipe but ordered a eBay pipe just for the seal (didn't use that pipe as the quality is terrible) 7 hours ago, LR5V said: timing belt side suggests poor fitment/sealing What I'm thinking, me an a mate did the block. I had to nip out and he finished putting it in an doing the belts. Asked him said he put in the seal correctly etc. Didn't add any extra sealant though Quote Link to comment Share on other sites More sharing options...
Rich Posted December 9, 2019 Report Share Posted December 9, 2019 Water pump usually leaks a little before it seals. Pink powder usually tells the tale. Still sounds like head bolts but compression isn't high enough to do it really Quote Link to comment Share on other sites More sharing options...
Prole Posted December 9, 2019 Author Report Share Posted December 9, 2019 So drove to the MOT passed, no coolant light on the way but come on the way back. Slightly pressured, come back up to the min line once opened, but settled back down to 1cm under the min line. But here's a few pics of the leaks. Wanting to look into these more but off to Germany on the weekend, so going to need to put it on the back burner for 2 weeks. Quote Link to comment Share on other sites More sharing options...
Rich Posted December 9, 2019 Report Share Posted December 9, 2019 New expansion tank, if that doesn't sort it then I'd start looking into steel seal and how to use it. Quote Link to comment Share on other sites More sharing options...
mk2 Posted December 9, 2019 Report Share Posted December 9, 2019 I'd be tempted to empty out the system, dry. Then pressurise to 15psi and put washing up detergent water on the outside. Find the bubbles... you've found the leak. All you need is a testing kit or a spare cap, fitted with a tyre valve Quote Link to comment Share on other sites More sharing options...
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