512TR Coolant in cylinder

I've reached closure on my problem and will update the thread with my ideas of the cause. Recall, the fan thermal switch failed, the engine overheated, and blew coolant out of the coolant tank overflow tube. On the next two starts I had white smoke from the right bank (Tubi where left & right exhaust don't mix). When parked coolant ran out the right tailpipe. On later starts, no smoke so I continued to drive, putting up with a coolant leak somewhere around the water pump area. With a light and mirror I could never pinpoint exactly where it was. I added one quart coolant mix every 100 miles, being very careful to check level frequently. Plan was to pull engine and do the water pump and timing belts which were only three years old. Plus check for a cracked head or blown gasket.

Well, time got away and in 16 months drove it an additional 5500 mi. with no problems except having to run with a zero pressure cap, add coolant, and worry, worry. With a good cap, coolant poured out from right front of engine.

About a month ago I pulled the engine and here's my conclusion, right or wrong. A bad leak developed around the water pump housing (more in next paragraph), coolant level went down, either the fan thermal switch failed or air was in the system causing it to give a false reading and not close the contacts (I'll never know), the cap cracked losing pressure, coolant blew out the overflow tube, and entered the exhaust system through the bad donut gaskets at pre-cat to test pipe junction. After this coolant burned out, no smoke on later starts. I had an oil sample analyzed by Blackstone and found no coolant in oil. A compression check revealed no problem.

With engine out, I pulled the water pump housing. It is about 3" in dia. with an "O" ring fitted into a machined surface in the back engine case. This area was beat to hell. Some idiot or jake-leg had beat it up, probably while trying to pull the main water pump seal out. It is hard to get out, but no excuses accepted. Whether the last shop doing the water pump did it or not, they were responsible for leaving it that way and setting me up for a big problem. I sanded the surface smooth and had to fill some gouges with JB Weld and sand again. The new "O" ring was coated with the proper sealant and then another sealant for metal-to-metal contact was used between the faces of the two metal surfaces.

Other work done was new timing belts, new tensioner bearings, new shims on 29 of the 48 valves to set tappet clearance, leakdown test, new "O" ring on sliding shifter shaft, new NGK plugs, new interconnect fuel hoses between the two tanks, all new coolant hoses (except heater hoses). There were 19 originally and now 21 as explained in COOLANT BLEEDER paragraph. Also new thermostats, new pilot bushing in flywheel, new exhaust donuts where needed, head bolt torque checked, and many, many gaskets and seals. I took a good look at the shifter forks and the welded differential housing. Parties unknown had already replaced the prop shaft between rear gear box and tranny with the 22 mm dia. one. Mine would have left the factory with the 17mm light shaft.

Here's some tips I'll pass along to other doing this work themselves:

1. EXHAUST HEADERS: I couldn't remove the nuts and broke a 1/4" wiggler. Soooo, we pulled the rear wheel hubs and axles completely out. This is no big deal and I'd do it again in a heartbeat. On the work table the nuts were easy to get to with end wrenches. it was all much easier for us doing it this way. The engine will come out and re-install with the headers on, but you must have a leveler on the cherry picker as clearances are very close and the angle must be constantly changed to clear a crossmember.

2. BATTERY CABLE: The cables mate on the rear of the left timing belt cover. A tapered copper plug fits in a tapered receptable and was corroded as expected. I'll never know how the starter was working. I cleaned the parts and coated with corrosion-proof electrical compound. But it wouldn't plug together securely as I'd probably damaged the plastic housing and metal clip getting it out. So I soldered copper terminals to both cables and bolted them together. Several layers of heat shrink protect the junction and a new Adel clamp holds it on the belt cover bolt. If anyone has starter trouble this ia a likely spot to check. It's easy to get to with the car on a lift or jacks.

3. COOLANT BLEEDERS: The 512TR has three bleeders. Two are in the upper metal tubes and one on the thermostat housing at firewall area. The parts book shows later models had hoses from the outer bleeders to fittings on the coolant tank so the system could self-bleed. The neck on my tank was cracked so I had a radiator shop weld in a new neck and at the same time weld in fittings for the bleeder hoses. New powdercoat and it appears to work, leaving only the center bleeder to check.

4. A/C COMPRESSOR: Since I had no A/C vacuum pump to evacuate the system I elected to leave the comnpressor with the car and not break the hose connections. This was difficult but I'd probably do it again. But if you have a vacuum pump, leave the compressor on the engine. Mine is an R-134 system and I've added one can at the 3 yr./10,000 mi. mark.

5. SEALANTS, COMPOUNDS, AND FLUIDS USED: For right or wrong, these are what I used. Dow-Corning #55 "O" ring lub for stationary "O" rings. It causes them to swell about 2%. Parker Lube for "O" rings with moving parts against them such as the shifter shaft. Lubriplate #105 for cam lobes. Permatex Locktite #515 for metal to metal on side and back of transaxle. Hondabond 4 at junction of large "O" rings and valve cover gaskets. Engine Agip 10W40. Transaxle Red Line 75W90ns.

Summary of the experience: Have plenty of mechanical skill, patience, and attention to detail before tackling this job. I'm a licensed aircraft mechanic and have thousands of hours of restoration experience, but this was the toughest thing I've ever tackled. The people that do it for a living earn what you pay them. What I did would have cost in excess of $10K at a dealer but I had in excess of 200 hrs. labor (mine and two helpers) because of the learning curve and excess amount of time cleaning and detailing parts. My parts bill was $1996. After a 145 mi. test drive it runs beautifully with no leaks or complaints and I'm left with a great feeling of satisfaction. Many thanks to those that advised me, especially Rod and Brian.

Picture below: I turned the clutch alignment tool on the lathe and an employee built the wrench to hold the cam gear while torquing the nuts. I will loan these to anyone for cost of postage and promise of return. The 1.25" silicone hose fits the four short hoses on top of engine. There's enough left for two cars and I'll cut it in half. I used a whole piece of the 1.375" hose so none of it left. PM me if interested.

Ron
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I think the surface must be fairly smooth for the "O" ring to seal. Sanding it helped and the big gouges I felt like had to be filled. After getting it to where the "O" ring would probably seal, I'd definitely seal the flat surfaces outside of the "O" ring, being particularily careful not to get any of the goop on the "O" ring itself. I used Permatex Loctite 515. It has to stand 15 psi under all kinds of temperatures.

We didn't put any more gouges on the surface getting the seal out. It's been three weeks ago and if I recall we used a small puller with a slide hammer on it. The seal came apart and took a little more prying. The inner oil seal came out easily by drilling two holes for sheet metal screws and one tap with the slide hammer puller and it was out. Don't trust the torque setting in the manual for the impeller nut. It stripped before reaching the specs so I used the old nut at a lower torque. A terrible sinking feeling not knowing if it was the nut or shaft!

Found two more invoices bringing parts total to $2200. I try to put them out of my mind and enjoy the car. Drove it another 100 miles today for total of 245 mi. and no problems. I used to have a rough burbling sound out of the right exhaust at idle and that is gone. Maybe the NGK plugs helped or the exhaust leaks getting fixed??

A new irritating problem; the radar detector constantly has a dim beep for one of the bands. It's not the loud one, but annoying. All we did to it was disconnect the wire plug from the rear detector. I can't even find the unit in the interior to check it out. I'll have to look up the brand but we're getting ready to leave for long weekend, so later.

Ron

 

Forgot to tell that I have a fan switch mounted in the center console where I can turn the fans on any time I want. I don't trust the system and get real goosey in slow traffic. Ron

 

I'll do it when I get home and can post a picture. It's very simple to do. I'm in Dallas now and won't be home until late in the weekend. Ron

 

Here's the pictures of my added fan relay switch and the schematic. Schematic isn't the best but I think you can figure it out.

1. The small toggle switch in the right side is a SPST to operate the radiator fans from the driver's seat. The middle rotary switch is the radar detector. Remove the plastic tray by removing an allen head screw under the radar switch. Remove the rear tray with another allen head screw under the rubber pad in bottom of tray.

2. At the left radiator tap a wire into the two wire harness that goes from the thermal switch to the fan relay in the front trunk. Determine which wire is the correct one by alternately grounding the pins in the plug with the ignition switch on. The one that starts the fans is the correct one. To be certain the ground is good, I added a short wire to the other wire and attached it to chassis ground close by.

3. For easy access to the thermal switch I removed the left rear tire and wheel and inner fender shield. I used #18 aircraft wire that has a very durable insulation but also ran it through plastic spaghetti tubing from the radiatior to where it went through the firewall. I routed the wire up to the cooling pipes and to the right side of the car. Where the large electrical cables go through the firewall to the ECU's I ran the wire into the car interior through a slit in one of the rubber bellows. Remove the panel covering the ECU's back of the passenger seat and you can route the wire to the console and pull through with a fish tape where it is concealed. Remove plastic parts in console as in para. 1 above. At the SPST switch, connect a short wire to the other terminal and attach it to one of several ground screws you'll find in the console.

This switch is no 100% guarantee of turning the fans on, but if the relays or fuses haven't gone out, and the fan motors are working, it will turn them on every time. I've had one thermal switch fail and thought another one was bad. It was acting up so replaced it. A $25 switch is all there is between you and a $25,000 bill if you don't catch it in time.

Ron
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