Water Pump?coolant leak

[Qgrappler]

My 94Q has developed a coolant leak, but I havent been able to see where it is coming from. I left it at the local gas station where it was when I noticed it, and they couldnt find the leak either, although they said they tought it might be the water pump.

The local dealer has said they have replaced some water pumps on 94 Q's.

Any clever ways for me to check this one way or another? the leaks do not appear to be catastrophic leaks, but at some point coolant got sprayed through the fan and sprayed all over the front of the engine, so one conclusion is the leak has to be coming from somehere above the fan where it can get into the fan blades.

Anyone else had new water pump experience on this vintage? andy ideas on cost if itturns out to be the pump? the gas station said the "book" indicates six ours of labor.

Thanks to all

[PalmerWMD]

I had a mystery leak before as well.It came from not properly tightened clamps (at dealer) on a couple of hoses.

Fred..

[nadirgholi]

Mine did the same thing earlier this year. Replace the coolant caps. There are two of them. The one that seems to be causing the problem you are describing is the one in the middle of the engine right above the fan (pressurized.) The other one is on the top right hand side of the radiator (non-pressurized.)

I changed both of them. No problem since.

[DAEDALUS]

SIX HOURS??? What book are they looking in? Garage Work for the Mechanically Declined? No six-hour job is that, unless they charge you to let the RTV cure. I can do it in 2 hours and I work fairly s-l-o-w-l-y.You have to remove some "fluff", which is my term for things like plastic shrouding and trim. Then off comes the fan belt and then the fan clutch (with a gear wrench, you don't even have to take off the fan!). The water pump is right behind the clutch. It's held on with 5 large bolts. Remove the bolts, then thread them back on 3 threads. Tap on the pump with a rubber mallet until you break the RTV seal. Remove the pump and the bolts. Apply RTV to the new pump and bolt it back on. Everything goes on in reverse order of how it came off. Water pump is about $70 from Scottsdale if I remember right. If you're in there, you should replace the thermostat ($12?) and inspect the thermostat housing for corrosion. If it's corroded, then great--its doing its job. Replace it.Having said all that, I wonder if maybe the radiator is leaking? Or possibly the upper hose where it attaches to the radiator? Has the car overheated recently? Is the spray on the engine more to the right or to the left of the fan? Look at the front of the engine from under the car. Sometimes a change in perspective is very informative. Feel under the upper radiator hose for dripping coolant. The hoses are cheap; the pump and radiator aren't. The laws of thrift demand that you look for faults in the cheaper things first.

MY 200th POST!!!

[DAEDALUS]

Allow me to clarify--the thermostat and housing are directly above the pump. Same routine...undo bolts, break RTV, replace. Unless you can remove the drain plugs in the block, you'll have to be prepared for the flood of coolant when you remove these items.

[Q451990]

Amen to the labor time... two hours max. Best thing to do is clean everything up and then check for new water marks. Most pumps fail from 60-80K unless you've maintained the cooling system exceptionally well (long life coolant and distilled water flushes annualy).

The filler neck cap is a common leaker as well - and an updated design is available.

Heath

[Qgrappler]

UPDATE

Now that its Sunday afternoon with more time, better light, and some guidance from above posts, I believe my problem is likely to be the radiator cap.The main cap has a rubber gasket which is hardened and cracked partly around its circumference. Given the amount of coolant that seems to have leaked out (I think its not all that much), a spraying cap would be a likely culprit.

The water pump area shows no signs of being the source of the spray. [ I also looked closely to make sure it wasnt fluid from another system like ATF, but am 99% certain it is coolant. ] During the episode, the temperature gauge didnt go above normal.

Thanks to all. Will update if anything is different.

[Jberger]

Qgrappler, I had the same issue, I chased the leak for a few weeks until I remembered the second cap under the shroud. Changed it out and the problem was solved.

[Qgrappler]

Final update, I think.

After changing the radiator caps, we had another episode, and I refilled the radiator and decided to look underneath the car after a partial refill, where I saw a steady stream of coolant leaking.

After raising the car and mistakenly thinking it was the drain c*** leaking, a got underneath and could clearly see it was a hose from a radiator fitting directly above the draincock, which is associated somehow with the transmission cooler. The hose is cracked at the clamp. Bad news is that no one had one in stock, so will have to wait to fix unitl Scottsdale sends me the one they ordered. [their still cheaper than the two local dealers who didnt have one either, but want almost double their price!!]

Thanks to all who replied

[landtodd]

The hoses under the plenum are a prime place for coolant leaks to develop, as they harden with age. They're hard to see, but coolant they leak will puddle a couple of inches deep in the motor's valley. Pulling the plenum off is NO fun the first time you do it. It's not even amuzing the second time.

[Qgrappler]

Well I was wrong about the source of the leak. That hose carries ATF , and the leak appears to be coming from around it not from it, where it enters the radiator, so it looks like I need a new radiator. Im assuming theres no way to dissaemble it and fix that leak. It leaks with no pressure after you put about a quart or more of water in the radiator.

Local quote for radiator is $531 vs $430 or so from scottsdale, prior to shipping, and also $280 labor to install it. Need to decide what to do. Having taken the thing nearly apart, doesnt look too terrible to disconnect all the hoses drop in new unit and reconect. Anyone been there and done that??

[DAEDALUS]

I'm just a bit confused here, but maybe only because our cars are a little different. Is the draincock on the driver's side? Or are your ATF hoses on the passenger side? On my '90, the ATF fittings in the radiator will leak if not tightened down enough. The fittings protrude from the inside out, and a thin jamnut (maybe 19mm?) is threaded on from the outside to lock the fitting down. If this nut isn't tight enough, coolant will leak from around the fitting. Check to see if you have the same configuration and, if so, try tightening the jamnut.

[DAEDALUS]

If you can stand to be without the car for a few days, I certainly would not rule out being able to fix it. Remove the radiator (not a big job), flush it out well, and let it dry. See if you can disassemble it to replace the ATF fitting from the inside. If not, then consider using some JB Weld around the fitting. It doesn't sound like anything that alone will affect the cooling efficiency, so if your radiator is in otherwise good shape, then do what you can to save the cash. If you absolutely must, then replace the radiator. Either way, you may want to consider replacing the temp sensor.

[landtodd]

$280 labor for a radiator? Good heavens. You could use that money to buy all-new radiator hoses (3), a fan clutch, a thermostat, and a flex-fan from Scottsdale, and a B&M transmission cooler, too (I don't think I'm up to $280 yet.)

It's not hard. The secret is getting the fan-shroud out. After you disconnect hoses and bolts from the periphery and bottom of the fan shroud, there's a plastic bottom part that you remove, and then the whole shroud slides up and out. Unbelievably quick & easy.

Hey! Change the belts while you're at it -- they'll never be easier to get to!

Use only Havoline Orange coolant and distilled water (yes, I'm now convinced) for your refill, and good luck!

[Qgrappler]

Well, on the 94Q (first one with the grill) the radiator has four fittings on it that appear to be ATF fittings. The draincock is on the passengers side, and the ATF fitting AROUND WHICH the leak is occurring is just above it.

I saw a somewhat rusted nut around the fitting, and wondered-as you have suggested-if I could fix this by tightening it. Maybe I'll give that a try. I dont quite understand whats behind that fitting, although it has to be some type of "heat exchanger" to keep the atf isolated from the coolant. The fitting comes out of the tall, narrow, "tank" on the side of the radiator, and the parts chart looks like this would come apart, although for the life of me I dont know how you would ever get a watertight seal between this part and the radiator fins. In any case, I dont think there is a prayer of getting a wrench or socket on it unless the radiator is removed.

Will investigate further and report.

[Aus94Q45]

It is a plastic radiator case and probably not a good idea to glue it or try other makeshift repairs -- given that a malfunction can cost you the block. Mine went and I had to replace it. Plasitic is plastic and it gets brittle over time with hot and cold extremes. They crack around the fittings as those are stress and vibration points. It is likley that even if you could stop that leak, a new one will appear in short time. Then you get to take it out again. Not worth it.

If the OEM cost is too high, you may want to check into after market metal replacements, however, they are not OEM and you gain some weight -- maybe a little cheaper. If you go non-OEM be sure that the rows of cooling meet or exceed those of the original. Also, the '94+'s supposedly have better cooling than earlier models (a big plus) so make sure that your mechanic orders the right one.

[DAEDALUS]

I agree that plastic is plastic, but I believe it's a fairly stout design. Ultimately, the real cause of the problem needs to be figured out before a decision is made, but here's my take. Agreed, if the plastic is cracking, then replace it (you may be able to replace only the tank). If it's a bad gasket, then I would try to repair it rather than replace the entire radiator at $400+. I have to disagree about there being much risk of destroying the block. I assume the concern is with plugging a critical coolant pathway with adhesive? The fitting is basically a threaded tube that protrudes through a hole that is probably at most 30 mils oversized. It's in the tank, right?...so it's not a critical pathway and with a viscous adhesive (and assuming full cure) I doubt any will squeeze in there and break off. Beyond that, there should be some kind of gasket behind the tank face that would most likely prevent any adhesive seepage into the radiator. I believe the only risk, and a very tiny one at that, is that some cured adhesive might get into the cooling system and slowly damage the pump impeller or restrict a single transport tube in the radiator. It's at least worth considering before plunking down over $400.

[911/Q45]

My first Q radiator cracked in that area after a bad mechanic changed the A/C drier without removing the radiator. Of course he just stressed it , so the plastic fatigue cracked about 6 months later and I got to buy my own part. Your radiator is probably about due for replacement anyway, go for it.

[Qgrappler]

Well, I have pulled the radiator and now can see the problem clearly. The leak was not at the fitting for the atf cooler entry, but was occurring at a crack in the plastic just above the lower fitting. When I refilled the radiator with about a quart or more of water, it seeped out through the crack and ran down over the fitting making it appear like it was the fitting that was leaking.

God only knows what would cause a crack there, although it is in the area where the "heat exchanger" would be for the atf fluid, so maybe it gets hotter there than other places.

Also, I think this must have been a problem that started small and grew larger rather than just one quick failure. because there was a fiar amount of rust on the nut below and the clamps.

Anyway, I am ordering a radiator tomorrow from Scottsdale Infiniti which is going to be $100 cheaper than the local dealer even after paying for air freight.

One person suggested I change the belts while I'm in there, and I think I will. Any other suggestions for preventive work to be done or tips on tricks when changing the belts?? [ It IS nearly 9 years old]

[911/Q45]

Wouldn't hurt to change the radiator hoses and check the water pump, thermostat and two cadmium pieces that corrode instead of your radiator and engine. Don't forget to remove the battery and rinse the goop out of the overflow bottle in the fender.