I have a 98 Cavalier Z24 with the 2.4 that is driving me crazy with a coolant leak and am hoping that someone can give a little direction on this.

It only leaks after the engine has been shut off and not all the time. When it does leak, sometimes it is a lot and sometimes it is just a little. I have no overheating issues. It gets up to temp and that is where it stays no matter how hard it is being driven or what the temp outside is. After scanning the forum I at first thought it may be the water outlet on the drivers side. Went and got a new one and when I pulled the old one off it was toast. Barely anything left of the lip for the o-ring and pretty much in horrible shape. Replaced it and hoped for the best. I guess I did not hope enough because it is still leaking.

The funny and pain in the butt part is that it only leaks after it has time to cool down a bit. This makes it difficult to see where it is leaking but today I managed to see it dripping and get a general idea. I saw it dripping and managed to get it jacked up on one side while it was still dripping. It is dripping from the same area as the water pump however I am questioning if it is indeed the water pump. As I said, I have no overheating issues and this problem has been with me for about 6-8 months. I did manage to see the connection where the thermostat is and it is dry. I took the heat shield off the exhaust and reached down to the water pump to and came back with some grease on my fingers but no tell tale antifreeze. Now it is more frequent however when it started it would only leak about once a week or so and even less in the winter. As you all know trying to look up at the water pump is an impossible task and a good visual inspection is impossible with the car in one piece. I question the water pump as well due to the fact that the point of contact on the floor is not always in the same spot under the car. Sometimes it is more to the passenger side (waterpump) and other times it is closer to the middle of the engine. It almost seems that the coolant is finding a line, hose, or other path to follow each time. Today it's final point of contact on the car was the oil pan and dripped to the floor from there. I have read other posts that indicate perhaps a heater hose but I have checked them and they seem dry.

I am thinking that perhaps I should put my focus back on that water outlet I replaced. Being just a very thin o-ring perhaps I managed to dislodge it from the groove on the outlet when I was installing it or maybe it is just not sealing. I was thinking that maybe I should pull it back off and make a gasket to the mating of the outlet to the engine to see if that solves the problem.

Anyway, that's my issue. Any wisdom someone may be able to share on this would be greatly appreciated.

Regards

Bob

Heater hose, behind the engine with a pastic piece is my suspect, it is a double hose.

An engine leaking coolant only when cold is absolutely to be expected. In the auto repair business, it is best to have the car overnight to locate a coolant leak. When things are cold they contract thus any bad gasket, loose fitting, loose clamp, etc. will manifest itself cold.
Once the engine is up to temperature all of these components warm up and expand thus sealing themselves.

If you can beg borrow or steal a cooling system pressure tester, put it on first thing in the morning and pump it up. The water will come pouring out of the defective joint.



http://www.amazon.com/Stant-12270-Cooling-System-Pressure/dp/B0002SRGWU

Dave

Keep us updated with your findings.

Hey, had the same problem with my girls 2.4. She was peeing out coolant for about a week, I too thought it was the water pump since thats where it was wet and leaking. Well, turns out the waterpump is fine, and like Luis said, the heater core hoses were the culprit. It would actually shoot out of there during cooldown, and run along the back of the engine, and drip right below the actual waterpump. Thus making it look like the water pump. Best thing I can tell you is this. With the car cold, reach back there with ur hand and rub the bottom of the water pump and see, is it wet? If so then yes, it maybe ur pump, but if its the heater hoses, everything else will be wet, but ur pump will be dry especially around the wheep hole. If its the heater hoses, I had no luck finding any at a local parts store, so I just bought some 3/4 heater hose, and worked them in there so they wont kink, and boom, done and fixed with about 2 hours of work, and maybe 15 bucks worth of parts. Goodluck!!!

Thanks for the input.

I did not want to spend the cash on a fancy pressure tester so I rigged up something out of some hose and misc. parts. I figured all I had to do was to get some pressure into the system. Rigged this up yesterday because yesterday morning it had a very large pee on my garage floor so I thought I better get on it. Left it over night so it would be cold.

When I went to the garage this morning to do the test there was not one drop of coolant. As I said, sometimes it leaks, sometimes not.

Anyway, I turned the line pressure of my compressor down to about 15psi, hooked it up and heard a bit of a gurgle then nothing. Unhooked the pressure, re-hooked the pressure and then my leak appeared. Got feeling around down by the water pump and it felt wet. Took a rag dried it off and checked it again. It was then I realized my life sucks. Weep hole.

This is not an adventure I was looking forward to. Not happy about having to dismantle half the engine to do this. Personal opinion is that the guy who designed this should, by law and penalty of pain, have to go and help each and every person who has to change one of these out.

Any advice on the water pump change would be greatly appreciated. Was looking at all that needs to be done (Haynes, Chilton, Autozone) and there are a couple of things that do not seem to be clear. First the motor mount that has to come off. Looks like a puzzle, and second the balancer. Looking down the side of the engine it seems like it would be easier to remove the front wheel, plastic splash shields, and then remove the balancer.

If anyone would be willing to do it for me in exchange for a case of beer or a bottle of your favorite and a hearty handshake then we should talk. Aware that the chances of that offer being accepted are slim I will settle for any wise advice.

Thanks again.

Hey man. Sorry to hear you have the water pump problem. It is a PITA but while your there, you can check the timing chain, guides and tensioner al the same time, and replace whats needed, I would replace them all since your there anyways, so you dont have to worry about it.

The mount has two bolts on the top when looking at the engine, there is a big bracket that comes off, and looks like 2 bolts are holding onto another bracket going to the frame rail of the car, those two bolts need to be removed, with a jack under the motor, and a little tension on there so nothing falls, you can get the other bolts under that bracket on the engine side off through the splash sheild, and just remove the mount on the engine side. You can also remove the mount on the car side I think IIRC there are 3 nuts holding it down. Not hard, just takes some looking at to see what im talking about and the mount will come out and be out of your way.

The crack pulley is just the one big bolt. But unless you have a way to stop the engine from spinning the only real way your going to crack that loose is with a good impact gun and a full air tank. Other then that, the books can walk you through, and there is a manual here for download that will tell you step by step on how to get off.

Your going to have to remove the wheel and crank pulley. There really isint a way around it. And I really dont know how to get that bolt out except with a good impact. Goodluck with this, and sorry it wasnt the easier heater hoses. Goodluck and take your time, and if you get frustrated, walk away before you do something wrong or worse break something.

Replacing the water pump is a big job. Too big for me. Heck, I even had one repair shop refuse to do it because they said it was such a big can of worms that they didn't to risk having it take way longer than their estimate. I have two 1996 Cavalier LS convertibles with the 2.4L engine. One of them needed a new water pump after 6 years (38k miles) which cost me $728 including parts and labor (here in expensive Silicon Valley). The other one needed a new water pump after 11 years (62k miles), which cost me $1023 including parts and labor. In addition to replacing the water pump, the shop recommended putting in a new gasket, thermostat, and timing chain tensioner, which is included in the above prices. I seem to recall one shop saying that you have to be careful to mark the timing gear and chain, and then line up the marks when you reassemble it or you can blow up the engine.

What stinks is that the water pumpitself is only like $90. But there is about $900 of labor involved because GM buried the water pump. It makes me really mad that GM buries the water pump even though they know that water pumps aren't long-lasting parts. This bad design turns (what should be) a $250 repair job into a $1000 repair job. For parts that wear out like alternators, DC motors, and water pumps, GM should make those parts easily replaceable. I guess GM thinks people don't care about the total cost of ownership and that stuff like this won't affect people's future purchasing choices. It's no wonder that GM is losing market share.

This is a big job.

My OEM pump is still running well at 190k miles. Didn't GM improve the pumps at some point, making them more reliable?

I think my 2000 has one of these newer pumps. IIRC, GM improved the oil flow through the seal or something like that. At any rate, I would probably have the job done by a professional unless I get laid off and have a ton of time to work on my car.

It is no doubt that the water pumps are in a bad spot. And it is no wonder they commonly leak after such short periods of time. But this is due to harmonics from the timing chain. The water pump doesn't have a smooth drive like a serp driven pump. However, GM recognized ths and issued a bulletin addressing this issue. Their fix is to install what looks like a maxi-pad around the water pump to collect residual coolant from the weep hole. Kind of a pointless fix for a problem that is not going away if you ask me.

Anyhow, to replae the pump, I found it easier to remove the exhaust manifold / header (depending on what has been done to your vehicle), and the cross over tube that houses the thermostat under the oil pan.

And as far as replacing the timing chain, good preventative maintenance idea. The chain and gears are not indexed. The upper gears have 8mm holes in them that align straight down fro the centerline of the cam bolt. I use 8mm or 5/16 bolts to keep them aligned. The lower gear has an indented dot on it on the side of one of the sprocket teeth. That aligns to a mark on the block. I would also recommend replacing the gears and guides as well as the chain tensioner. Make sure to follow the instructions for the tensioner letter for letter otherwise you face doing catastrophic damage to your bottom end and your cylinder head.

Removing the bolt for the balancer can be done many ways. I have put a breaker bar on it and propped the breaker bar against something, then bumped the starter. 99% of the time, it will break the bolt loose and you can remove it like that. I don't recommend that for everyon unless you have seen it done or done it yourself before. But the best bet is using a strong impact gun and a lot of air.

The whole job really isn't that difficult, its just time consuming. On a dificulty scale of 1 to 10, I personally give it maybe a 6.



Some people have brain storms, others light drizzles. And then there are those that have droughts.

so sorry about your water pump and Iknow you probably don't want to hear this but don't touch that water pump... take it to a shop and let them fix it because if anything goes wrong or anything breaks they will be responsible and will have to fix it for free.

it sucks that you have to spend so much on labor to replace a cheap water pump and if you can't find anyone who knows how to replace it then. borrow money, get a loan, do whatever it takes and get it fixed asap or one day you will be driving and then its really going to go out and it will overheat and it could warp the head gasket surface, then you have another, bigger, way more expensive problem'
just for a headgasket kit is 200.00

that is my wise advice

From my experience they commonly leak in two places, the water outlet on the driver's side of the motor and the heater hose pipe underneath.
Original water pump on my car with 458 000 km.

FYI
The 98 model year z24 is known to have water pump problems, that's why GM changed that item for the 1999 model year.