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Water pump broke 1997 5.0

02-19-2022, 02:13 AM
I was changing the water pump on my 1997 Mercury Mountaineer 5.0 and it appears the last person to do the job broke one of the medium length top drivers side corner bolts off. To “fix” this they covered a shorter bolt with gasket sealant and stuck it in the hole. It doesn’t appear to have been leaking.
I do not want to pull the timing cover and try and fix it.
I have the new pump on with new bolts. I used a little sealant on the ends of each bolt and tightened them to spec.

This is a beater car that is probably headed to the junk yard in a few years. I am thinking about sticking a longer bolt in the hole covered in JB Weld. If the gasket sealant worked on a short bolt just stuffed in the hole I’m thinking a longer bolt that actually makes contact with the the block with JB on it would be even less likely to leak???

Yes, I realize this is NOT the “proper” way to do this but I have no interest in fixing something that was not leaking before with an even worse idea for a fix. I am definitely open to other suggestions or “tricks” other than pulling the cover and drilling what is most likely a rusted mess.

Thanks 🍻

02-19-2022, 08:34 AM
For starters, are you sure there's room for a longer bolt in that hole? Often those bolts break due to being seized in the timing cover (galvanic corrosion) and not necessarily from being seized in the block. So I'm not so sure, unless you've already checked, that a longer bolt would make it to the block. Also, if you're not threading into anything it doesn't really matter how long the bolt is, it's not going to be providing any sealing force to that area of the water pump. Your more effective place to put a sealant (and not JB Weld) will be the gasket surfaces between the water pump and gasket and the gasket and timing cover. Let the RTV gasket maker partially cure per instructions, install, then allow the full cure to happen. Properly torque the bolts that still thread into metal. At that point, putting bolts into the holes with broken studs is purely for appearance.


02-19-2022, 11:11 AM
Thanks Rod. The bolt that the guy used last time was an inch and a half covered in sealant. When I put the socket on it and started to turn it it fell out. I thought I had broken it till I cleaned out and chased all the holes and found that a 3” bolt would go almost all the way in before hitting the hole with the broken bolt in it. I stuck a long punch in the hole and it feels like there may be a couple of threads left before you hit the broken end.
So the 1 1/2 bolt was there purely for looks!😱. I assumed that he filled it full of sealant because that bolt went through a water jacket.

I thought maybe I could get a long bit and drill the center out a little deeper and create a cavity and then cover the end of the bolt in JB and the shank in sealant. But I agree with you that it’s unlikely even when cured that it would offer any clamping force. I may be better off just buying some Flex Seal and cutting a bolt to fit all the way in till it touches the broken part. It worked for at least 3 years since that is as long as I have had the truck.

I did do exactly as you said and put sealant on the pump and then laid gasket on and let it cure. Then I put more sealant on the gasket to timing cover side and send new bolts with sealant on them. All and all I think it should be sealed better than it was before. I used a quality gel-pro gasket compared to what looked like a paper gasket that was on it when I pulled it off. I swear the guy used house hold caulk to seal it last time. The sealant was white!!!😱

I hate doing things half assed but I don’t have the time to fool with it!!!🤬😢

What do you think of the flex seal idea?


02-20-2022, 07:48 AM
I just put a water pump on my son's Bronco with the 5.8L engine and two studs broke on it. Fortunately they broke with enough sticking out of the timing cover that I was eventually able to use the induction heater to back them out. In watching videos though for suggestions on the process, several of the videos I came across were of the same scenario but on the 5.0L engine and it looked very similar to the 5.8L. So I'm not sure if they are the same block, but at least on the 5.8L it didn't appear that any of the bolts went into water jackets. The corrosion that caused the two bolts to break appeared to just be galvanic corrosion from the aluminum timing cover because once I got the corrosion in the timing cover softened up, they threaded out just fine.

That was a bit of a long story just to say I don't think you really need to worry about using Flex Seal on the bolts, and I don't really think you even needed to use any RTV on the other bolts either. I used a bit of anti-seize on all the bolts when I installed the new water pump since the service manual didn't make any mention of using sealer on the threads. FWIW, the same service manual instructions cover the 5.0L, the 5.8L MFI, and the 5.8L MRI Lightning engines.


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