Coolant Leak

[jmgtp]

Just when I thought it was running great!

I developed a mystery coolant leak. It appears to be coming from the timing cover area and I can't quite pinpoint it. Cold engine doesn't leak and a hot engine drips. If I get on the gas hard when I come to a stop I get coolant steam coming out of passenger hood louver. It isn't the steel heater core line and it is also not the waterpump. I pulled the timing belt cover and there is A LOT of moisture on the inside of the covers. I suspect it to be the freeze plug in the rear head - I replaced both heads a few months ago and since then the front head lost a freeze plug so that leads me to believe the freeze plug in the rear head is ready to fail/pop out.

Is there a downside to using the rubber plug with the tightening bolt? I can access the plug with the timing belt tensioner plate removed and I think I can install the rubber kind but if they are prone to failure I'll pull the head.

[pocket-rocket]

I would use metal if it were my car. I don't have any proof that the rubber ones would be any less reliable then the metal ones, but then again engine builders have used the metal ones for decades.

[jmgtp]

Well... I took the timing belt off and removed the tensioner bracket so I could see the freeze plug and it is positively the source of my leak. There isn't enough clearance to remove/install with the head on the car. So I tore it down AGAIN. I have the head on my bench now... the freeze plug is leaking through a pinhole but it is still firmly pressed in, how do you take these things out? I'm a bit scared to use a punch and hit it off center to try to get it to spin, I think I might drive it in further. It is steel so I can weld a long piece of metal to it and pry it out if I have to but I would rather not since that kind of heat can really screw with the aluminum head. There has to be a known way to remove these.... someone enlighten me! Thank god headgaskets/bolts are cheap!

[ratrodder]

try drilling a hole and using a sheetmetal bolt or something that would grab with a pair of visegrips

[jmgtp]

Freeze Plugs...

I may try that if the punch method fails.

2 questions:

Freeze plugs are available in brass and steel. Which is better? I've read that the brass is superior due to its corrossion resistance and some claim (googled) that they seal easier. Brass is a softer metal so I imagine it would conform easier to the head and maybe that is how it is able to seal better.

What is best method to install them? There seem to be two methods, one using a large socket or seal driver and driving the plug in using its hole circumference as the driving point - which is how I had done it before and that led me to a plug popping out the front head and leaking on the rear head (these were steel plugs). The other method is to use a flat punch and strike the plug directly in the center, this is supposed to cause the plug to expand and seal as it is driven in.

Thoughts? I absolutely do not want to do this a 3rd time due to freeze plugs!

[ratrodder]

I would think you would want steel on an aluminum head ( the rubber freeze plugs are a fix) have not seen brass but thats not saying it hasnt been done, do you know for sure why they did not seal ?, size or not seated properly? do you have a machine shop that you deal with if so I would ask , I feel your pain about having to tear it down again

[jmgtp]

The machine shop I used to go to is no longer around.
Autozone/Advanced - I would rather ask my grandma for advice!
NAPA is hit or miss. The original plugs were steel so I guess I will go with that since they are proven to work. The plug I installed in the front head popped after about 20 minutes of run time on the new heads. I have no idea why it came out, it fit tight and was flush with the head. So I pulled the head to replace the plug and I 'staked' the rest of them... in doing so I put a small hole in the rear head/timing cover side plug. It was a stupid mistake. Not wanting to pull the head to replace it I took the easy way out and welded the hole closed and ended up with only a pinhole leak which I used sealant to plug hte pinhole. That lasted about 2 months until the sealant gave and here we are today - I pulled the head to do it right this time.

[jmgtp]

I ended up using a punch routed through a water passage to hit and deform the side of the plug and then it popped right out with a little help from a screwdriver. Installed the new one with a large flat punch, driving it in by hitting it in the center and then I also 'staked' it in a few places around the edges.

I put the heads together about 2 months ago and have maybe 1k miles on them. The exhaust valves were new and the intakes original but cleaned up. The valves on cylinder 3 and 5 look great. A light carbon film but they were still shiny. #1 on the other hand... the exhaust valves looked good, still shiny and just a light carbon film like #3 and #5. However, the intakes were already developing that rocky looking carbon deposit. Could this be an indication that #1 is running rich? I cleaned up the valves and the engine is mostly back together now. Just needs the timing belt reinstalled and it should be good to go.