My '89 Chevy Caprice Classic station wagon has a coolant leak that I initially thought was from the waterpump as it was dripping from the front of the engine. I looked with a mirror, though, and I'm not sure if it is the waterpump. The drops seem to be forming near the bottom of the engine's front beneath the crankshaft pulley maybe beneath the timing gear cover.

Are there internal coolant passages in this area that could have rusted out and started leaking? Am I looking at a major repair bill?

Thanks in advance for helping me troubleshoot this problem.

I almost forgot--like the Oldsmobile and Buick full size wagons of that year it has the 307 Oldsmobile V8 (VIN Y). It has ac, ps, and the air pump for emissions, so there are four belt driven accessories (including the alternator).

Also, if anyone knows of a good Oldsmobile forum and will post a link, I'd appreciate it. I checked out Oldsmobile Forums and Oldsmobile Forum, but neither seem to have a lot of traffic.

As a fellow owner of said vehicle, I feel your pain.

Heres a shot of a 307 laid bare in front for reference.

Here is a link to an article on a common coolant leak between the intake and head. Heres another page on water pumps, just for reference. Having owned Oldsmobiles for most of my driving life, I'm well aware of the cooling issues they develop over time. Hope this gets you headed in the right direction.

Thanks, FieroMojo, for the 307 photo and the links. Is it safe to assume that the leak is either from the waterpump or the main intake-to-heads gasket? It couldn't be coming from somewhere else, could it? I hope not since I can't think of what else would be causing it unless the block is cracked (we have not had any freezing temps).

How difficult is it to replace the waterpump on a 307? I've heard its more involved than a small-block Chevy.

What price range am I looking at to have a shop replace the main intake to heads gasket? I might consider replacing the waterpump myself. I don't think I want to attempt the gasket.

Thanks again.

Also, the droplets seem to appear below the timing gear cover, very near the bottom of the engine's front. I wiped it several times, and the droplets continued to form. If there aren't coolant passages in that area then it has to be coming from above, right?

You most likely have a leaking intake as Mojo said. I'm a big Olds fan myself, and have had to take a few of these things apart.

Replacing the water pump isn't too bad at all. It's about a 4 hour job in the garage, including several beer breaks. All you need to do is remove the fan, belts, A/C and air pump bracket, radiator hoses, loosen the power steering pump assemble ( including the bolt on the drivers side of the engine ), pull off the thermostat housing and bypass hose ( it's easier that way ), and the heater hose if it's attached to the pump. There are 4 larger bolts and I believe 7 smaller bolts holding the pump to the front cover, and it should be ready to come off. When you are pulling off the pump, you need to make sure that you leave the cover in place on the engine. The engine front cover is a thin plate that fits over the gearing, and the water pump bolts onto the front cover, with the pump bolts locking everything in place. Don't break the seal between the cover and the engine, or you may end up with a few more leaks. If you have a leak between the pump and the engine, you would then need to pull this cover and reseal it. That requires a few more bolts and pulling the harmonic balancer, which is no big deal with the proper puller.

Intake gasket? On the 307 it isn't too bad. It's a matter of clearing everything out of the way and labeling the hoses and wiring. Make sure the top of the engine is clean so you don't get any garbage into the engine valley. You'll need to pull the distributor, remove the carb, and remove the vacuum hoses and computer wiring. There are a number of other things to clear out of the way.......the throttle and trans detent cable, vacuum tube for the brakes, a few sensors, some of the emission hoses, EGR valve, and a couple of other items. Once clear of these, you should be able to get at all the bolts for the intake.

Once the intake is off, you need to clean up your gasket surfaces. Be very careful with the intake as it's aluminum and dents easy. You can really mess it up quick with any sharp scraper. Your new gasket set comes with new sealant for the intake, so make sure you use the right stuff. There will be two different sealants.....one for the intake ports, one for the water ports. When you have your intake cleaned out and your head surfaces are cleaned also, it's time to put her back together.

Pick up a nice Haynes manual. I believe they have a nice write up on exactly how to do this step by step, and it isn't a bad job. I've done it several times, and I'm just throwing this up from memory. I've replaced the intake gasket and water pump on several Olds motors, including my '86 307 and a '88 307 my parent used to own.

If we can be of further assistance, let us know.

Mark the Olds guy

Thanks, Firefox, for the info. I gave you and FieroMojo positive ratings. The weather turned cold, so I took it to Pep Boys rather than attempt it myself (I don't have a garage). It turned out to be the waterpump. They replaced that and the thermostat, but the technician was sloppy. He left off a screw on the fan shroud (not a major concern but still), one of the A/C compressor bolt heads was left in contact with the A/C pulley (the nut was barely holding on the end). I took it back the next day and asked them to check for any other loose bolts--they tightened the A/C bolt and said everything was ok. However, it's still leaking slightly around the water outlet spout. I thought it might be they didn't tighten the hose clamp, but it looks like they left off the nut on the driver's side holding down the spout. Do you know the size and pitch of that nut? A photo of a correctly installed spout would also be helpful. Thanks in advance!

I'm on my way out to the car. I believe its a 13mm and coarse thread. Not too sure how they enumerate pitch angle. Back in the day, it was a 1/2 hex, 5/16ths x 20 thread, IIRC. Pix and corrected info to follow...

So much for technology. Not only have they totally burried that nut/stud with all kinds of plumbing and gimictry, my newfangled digi-cam will not focus on the drivers side stud. The passenger side is a bolt and of course I have a great shot of that. If that nut is missing, its a 13mm but I cant see well enough to tell if its coarse or fine thread. Nuts are inexpensive so grab one of each just to be sure but I'm almost positive its coarse. Make sure you have a lock washer as well. If it still leaks after replacing the nut, its time to replace the gasket. Hope this helps.

[This message has been edited by FieroMojo (edited 12-18-2004).]

I just replaced the coolant overflow in my vette. I refilled it the other day, but since, after driving it a little bit, have noticed a few drops under the front of the engine too. Mine looks like it may just be some i spilled working its way down front frame member. I got under it on ramps yesterday to look and all around the front and under water pump looks dry. From the bottom theres a few stray drips of fresh antifreeze right on the front edge of the oilpan and oilpan bolts. Im gonna drive it a while more and see if it stops dripping. I dont want to get into fixing it, got other stuff to do. I know its not the water pump on mine, I can clearly see all around it and its totally dry.

FieroMojo, thanks for the nut specs. If you have time, please post the photo of the passenger side bolt. Lying off to the side is a metal strip or bracket with a hole in it that looks like it may have been retained under the bolt. If it should be under the bolt, can I remove the bolt to install the bracket without damaging the outlet gasket or will I need to replace the gasket?

I think I found the nut. It was lying under the wiring and vacuum hoses on the intake manifold behind the water outlet. Should there also be a lock washer?

On my 307, which is in my '86 Cutlass, I have the stud on the driver's side and just a bolt on my passenger side. The stud is there for one of the two holes in the bracket that holds the cruise control assembly. I don't have any retainer clips anywhere near the thermostat housing, so I'm not sure which clip you are referring to. I'll take a picture of my setup tomorrow for you and you can compare. I do have a factory Oldsmobile service manual for 1986 and a Chevrolet manual for 1988, which had the 307 in our full size Caprice Classic wagon. So, if we can't figure this out for you with my '86, maybe the '88 manual can help.

Mark

I would use a lockwasher to prevent the nut from loosening again. There is a bracket under the bolt on the passenger side... appears to be for the oil filler spout. You should have no problem dealing with the bolt as long as the other side has been secured first.

Shot of the gooseneck showing the bracket under the bolt

Shot of the oil spout and bracket... looks like they may be related

I would venture out today but "the weather outside is frightful"... looks like we'll be having a White Christmas after all.

Thanks for the photos. I took a closer look at the bracket, and it looks like it holds an electrical connector of some sort.

Its going to be warm tomorrow, so I'll be able to get the nut back on.

What should I torque it to (and the bolt too)?

Thanks again to both of you for helping me troubleshoot this.

Best wishes for a Happy New Year!