Engine Intermittent Coolant Leak

[tca7291]

So as the story goes, I drove roughly 90 miles yesterday and had no issues. Today I noticed a puddle of coolant under my car. (I know it was coolant, I did the taste test) I looked around the radiator, hoses, any cooling system component while the engine was cold, and found just a very little drip hanging off of my lower radiator hose at the water pump. (drip wasn't running, just residual) I hosed off the coolant on the parking lot and underside of my engine (I can't have the possibility of my neighbors animals getting in to that) and topped off my radiator and the puke tank. The puke tank was dry and my radiator was about 2 inches low from the filler. I took the car for a nice long drive, about 15 miles, running it up to operating temp, and higher than normal RPMs like 3k-4k. I can not get it to leak again, even after it has cooled off. I've never dealt or heard of an intermittent coolant leak. Anybody have any ideas as to what is going on???

 

[mikestang63]

Did you check all the worm clamps on the hoses? If you don't own one, go to Autozone and rent a coolant pressure tester and you'll find the leak.

 

[tca7291]

Yeah, that is my next step is to get a pressure tester. I checked all the clamps, they are all tight, but I don't know the age of the hoses, I guess I will go ahead and replace them anyway. I just really want to be able to recreate the leak so I can rule out certain components. For real, I am just baffled at the idea that I got the system naturally pressurized with my post cruise, and I still can't get it to leak at all.

 

[91TwighlightGT]

Gonna have to get a pressure tester, some things can leak intermittently.

 

[tca7291]

I just find it so strange, never leaked before, took the car for two drives today to get the cooling system hot, let it cool all the way down in between the drives, and still can't reproduce the leak. I'm gonna go to AZone tomorrow and rent a pressure tester. Hopefully that will show me where this leak came from so I can fix it.

 

[tca7291]

Ok, things just got weirder, I got anxious and used an air ram drain clearing tool on my radiator neck, pushed it to about 30psi and was able to hold it for roughly 15-20 seconds, and that wouldn't produce the leak. Could the leak be heat related?

 

[billison]

I've heard of cooling systems getting gummed up and spitting half the coolant out from too much heat. When was it flushed last?

 

[tca7291]

Damn good question, just got the car about six months ago and don't know much history on it.

 

[Maryland Stang]

Yes, heat can make a difference. I'd look at the water pump gasket. Or the water pump it's self. If it is either, make sure you replace the timing chain while you have it apart, if it needs it.

 

[mikestang63]

pressure test the system with the same amount of pressure as on the cap. think it's 16lb? Do not over pressurize the system. It should hold that pressure for 15-20 minutes without dropping. Also test the cap. There is a weep hole on the H2O pump and start to drip when the seals begin to fail. That could be the coolant running down the hose.

Not that it is the most accurate, but is your temp gauge jumping or running higher than normal.

 

[tca7291]

Yeah, I think it is the seals in the water pump going, it tends to only leak after the car has cooled off all the way. I did a pressure test with the car still warm (not hot) and I think when the seals cool off all the way and contract, it allows it to leak somewhat. It didn't leak or loose pressure. Maryland Stang, my car has 110K on it, would the timing chain need to be changed yet you think? I think I am going to do H/C/I next summer and will deff change the timing set then.

 

[mikestang63]

If you are going through the trouble to pull everything off, why would you reuse an old timing chain with 110k miles on it. lol Talk to Ed Curtis or Woody when you are ready and either can set you up with a wicked combo.

If you grab the H2O shaft, can you feel it wobble at all? Your weep hole should be on the bottom of the housing. Follow the lower hose up to the H2O pump. Can you feel it wet there.

Regarding the H2O change. Make sure you PB blaster all the bolts/studs before you try and remove them. They are prone to snap. I've heated up the housing and sprayed PB blaster in the bolt holes to get them loose some times. Often guys dont put anti sieze on the bolts and they crud up with rust over the years. When ( notice I said when not if) I need to replace mine, I will swap the bolts for SS parts. Do not buy a Poop boys or Autozone reman H2O pump. They are notorious for bad tolerances and premature failure. Good time to replace the stat and check the hoses while you have it apart.

 

[tca7291]

Yeah, thanks for the advice, I am planning on ordering a reman ford h2o pump from either LMR, or mustangs unlimited, I figure I am going to go ahead and do all the hoses and t-stat also, as I don't know the age of them, or even if they have ever been replaced. I guess it wouldn't hurt to go ahead and do the timing set also, it might as well be done while I got it all torn down. I have done the water pump on a few 5.8's before, so I already know about the bolts and anti-seize. I did trace the leak to the lower rad. hose right at the pump, so I am assuming that it is coming out of the weep hole. Thanks for all the advice though! I really didn't even think about the timing set, but you guys are right, at 110k I'm sure that chain is stretched pretty well.

 

[Maryland Stang]

Back in the old days before they started making better oils, it was guaranteed that the timing chain would need to be replaced at 100,000 miles. If you engine has had regular maintenance then there's a good chance you don't need to replace the timing chain. If it has less than 1/2" of deflection then leave it in there.

 

[ReefBlueHatch]

This is the same problem I had not long ago - thought it was the pump hose leaking and was leaking a puddle when parked. Crawled under and could see a trail were it was leaking from the weep hole on the water pump.

 

[mikestang63]

This is the same problem I had not long ago - thought it was the pump hose leaking and was leaking a puddle when parked. Crawled under and could see a trail were it was leaking from the weep hole on the water pump.

Yep, sure sign the seals are gone., which is why I never put a reman unit on. They may put new seals on, but the tolerances are often off and it's worth the extra money to me to do it right the first time. I have used the Ford racing and steward pumps for years with no problems.

 

[tca7291]

Yep, that is exactly what is going on, thought it was the hose until further inspection, it's leaking from the weep hole. As far as a replacement pump, I'm planning on getting the FRPP pump.

 

[Farmer83]

Yep, that is exactly what is going on, thought it was the hose until further inspection, it's leaking from the weep hole. As far as a replacement pump, I'm planning on getting the FRPP pump.

Look at the Edelbrock victor series pump,its a heavy duty,REBUILDABLE pump that offers increased cooling & flow (30% flow increase at 3000 rpm then back to normal)Flowcooler also has a nice pump for less $$ w/same cooling benefits.If you go this route be sure to install a heater core restrictor in the feed line at the intake side.Hope this helps.