Big leak around the Tee

[pdecker]

My late model A4 overheated and quit on Sunday after 40 mile run in hot weather running full throttle for the last mile. After I got the engine restarted, I noted there was no water coming out of the exhaust. The overheating happened suddenly, and was not overheating before. I read some online threads and removed the tee fitting, letting the diverter fall. It did not fall, like Don M said it would, and had to push it away from the opening in the side plate. I cleaned some debris out of the removed tee, and ran a cable tie in the hole to make sure it was not completely packed up inside the side plate. I also removed the thermostat housing and cleaned major black chunks out of the housing and thermostat. I blew into the hose after the thermostat housing and confirmed there is no blockage or restriction through the manifold into the exhaust pipe. (I had the manifold ultrasonically cleaned last year.)

I reassembled the cooling system, using Teflon paste in the pipe thread on the tee. I started the engine, and only got a little water coming out of the exhaust. HOWEVER, cooling water gushed out from around the tee fitting at the side plate. It is possible that I didn't screw in the tee as far as it was before removal. What is the next step? I'm hoping I don't have to take off the rusty side plate since I want to motor down to the lake for the long July 4th weekend and can't get it done before then. My ideas:

1) Remove the tee again and use Teflon tape instead of paste, making sure to screw it in fully? I hope I don't strip the threads on the side plate.

2) Leave the tee in place and pack it with Marine-Tex epoxy?

3) Remove the side plate to clean out all the gunk, risking breaking bolts off. It would be hard or impossible to drill out broken bolts because of the tight space in the Catalina 27 engine room.

Phil

[ndutton]

I'm sure your engine would benefit from a thorough cleaning but of greater concern is no flow out the exhaust. The late model cooling system is designed so that the exhaust gets full water flow regardless of engine temperature or thermostat position. That you have no flow tells me there's a major blockage after the thermostat housing (manifold, manifold cooling water exit or exhaust water injection fitting).

[pdecker]

I could blow air, but could still be blocked?

Great thought, Neil. I was able to blow into the hose coming off the thermostat exit, but there could still be debris in there that restricts water flow. I ran a long screwdriver into the exhaust water injection fitting and made sure that was clear. Today, I'll take the elbows off the manifold to check for debris. That's the only thing left.

I'm sure your engine would benefit from a thorough cleaning but of greater concern is no flow out the exhaust. The late model cooling system is designed so that the exhaust gets full water flow regardless of engine temperature or thermostat position. That you have no flow tells me there's a major blockage after the thermostat housing (manifold, manifold cooling water exit or exhaust water injection fitting).

[ndutton]

Let's check inside the thermostat housing too.

[pdecker]

Did that one.

Yep, I checked inside the thermostat housing last night. Lots of black crud. I rinsed it all out and scrubbed the housing and the thermostat with a toothbrush to get everything out.

Let's check inside the thermostat housing too.

[JOHN COOKSON]

. What is the next step? I'm hoping I don't have to take off the rusty side plate since I want to motor down to the lake for the long July 4th weekend and can't get it done before then. My ideas:
Phil

I think I understand what you are aiming to do. Hoping that if there is unobstructed water flow the water will no longer cause water to squirt out at the tee fitting? Good luck. If water doesn't squirt out it will probably leak out.
I've had the side plate off my Cat27 a couple of times. It wasn't to bad - only a few sore muscles and bruises. If possible use a 6 point closed end hand wrench on the bolts. That way you have a better feel for what's going on with the bolt; is it coming off easily or not. Go at it with brute strength and you will increase the chance of breaking the bolt. A couple of days treatment with PBblaster would be beneficial. Tap on the bolt a bit to settle the PBblaster in.

TRUE GRIT

[pdecker]

Found the real source of gushing water

Rust-through holes next to the tee-fitting! The side plate is shot. I removed the alternator in preparation for removing and replacing the side plate. I got three bolts loosened before a buddy came by with beer and I called it a day. I will post photos once I get it off.

[edwardc]

Glad you found the source of the problem!

Now, since you have to order a new side plate anyway, I would urge you to convert to studs on the side plate mounting and end the risk of broken bolts once and for all. MMI sells a kit for doing two holes at a time that includes the studs and a threaded backing plate. I did this pro-actively on my A4 at the time of the rebuild even though the side-plate threads in the block were intact.

[roadnsky]

Heed John's advise regarding those bolts or you may go much deeper down the rabbit hole!
Guess how I know...

[JOHN COOKSON]

Now that you have a start on cleaning up the cooling system and are going to take off the side plate, and if you plan on keeping the boat for awhile, it would be an excellent time to consider FWC.
Due to the limited work area and access on a CAT27 installing FWC would be somewhere between a pain in rear and impossible. If you were to blaze the trail others (such as I) might follow.

TRUE GRIT

[pdecker]

Photo of the old side plate

Here's the problem! I have three out of eight bolts out, and I will continue to soak the remaining five with Liquid Wrench until I run out of it. I will also be ordering the replacement stud kits for sure.

[edwardc]

Either Kroil or PBBlaster will penetrate much better than Liquid Wrench. Almost as good is a 50/50 mix of acetone and automatic transmission fluid (ATF).

And if all else fails, you can grind off the heads, remove the plate, and get a. vice-grip on the stubs. If any break off flush. You can drill them out.

[pdecker]

Finally got the plate off using all the above methods

Not pretty, but it worked.

[edwardc]

Wow! That's a seriously swiss-cheesed side plate! And a pretty mucked-up block too! Glad you finally were able to get it off.