Few Different Questions (Radiator & Piston)

So, I came to terms with the fact that I had a bad head gasket and tore into it today. I have a few questions. Please answer any/all.

First question, the 3rd piston in cylinder was clean on top (see picture link). Does that mean it was definitely coming in contact with coolant?
http://img702.mytextgraphics.com/photolava/2008/03/10/tire-49s8vtt2x.jpeg

Second question, the gasket looked perfectly fine. Would I be able to visually see if it were bad? If it wasn't bad, how would I check for cracks in block or head?

Third question, the whole reason this happened was that my heater valve broke. I'm upgrading to a 3 row open radiator and I need a new valve. Can anyone recommend a good place to get one and do I need a special one for the open system?

Last question, can the pressure bottle be used as an overflow bottle for the open radiator and if so, how?

Thanks for any help!

I don't think the pressure bottle can be used for an overflow because it is made to be under pressure. As a side note, you can omit the heater control valve. It is really not needed and just an additional failure point.

1) Correct. The #3 piston was being - quite literally - "steam cleaned." Clean the other five, and wipe off #3.

2) A head gasket can look good when removed, but still be "failed" under pressure. There is, after all, no pressure on the gasket when it's removed. And, it's usually more likely to fail where water is than where compression is (the flowing water serves to erode the gasket material slightly. The compression seals are usually reinforced with metal rings.)

3) It is entirely possible to use the pressure bottle as an overflow - but good luck finding a cap that isn't pressurised for it. I don't know what threads those are, or what else might fit.

4) The heater control valve may be safely deleted - I deleted mine a few years back, when I fabbed up copper plumbing for the heater lines. It's there to cut off coolant flow through the heater core when the aircon is on (my aircon failed a long time ago...) so it wouldn't have to work as hard. You might note that your aircon isn't as cool as it was, but that's about it. Without the heater valve, your heater core will probably last longer (since coolant is constantly flowing through it with the engine running.)

5) Checking for cracks in castings is usually done either with a dye penetrant kit (if you can find one locally. Magnaflux makes a good one, it runs about $30,) or you can take it to a machine shop to have it actually Magnaflux inspected. It costs more, and it's more work - but it also finds smaller cracks.

Thanks so much for the replies! I'm excited that I don't have to find a new heater valve, especially since my AC doesn't even work. I remember switching to an open radiator on my old xj and locating a replacement valve was difficult and I ended up going to a scrap yard. If only I would have known . . . Anyway, thanks again!

i was curious about the heater valve myself. i need either a new one or get rid of the damn thing and do what 5-90 has done. anyways if i get rid of it and coolant will keep flowing through the heater core, wont it be a bit hotter in the xj on a summer day? my a/c doesn't work either and i dont want it to get even hotter in the heep than it will. also, could i just put a valve i can do by hand in the colder seasons when i need to? thanks in advance.

- Dan

Cherroarkee said:

i was curious about the heater valve myself. i need either a new one or get rid of the damn thing and do what 5-90 has done. anyways if i get rid of it and coolant will keep flowing through the heater core, wont it be a bit hotter in the xj on a summer day? my a/c doesn't work either and i dont want it to get even hotter in the heep than it will. also, could i just put a valve i can do by hand in the colder seasons when i need to? thanks in advance.

- Dan

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A bit, but not much. I've been thinking about a cable-operated shutoff myself, but haven't gotten around to it yet. (I could build it into the next rev of my copper heater lines, so it would be - natch - brass, and I'd be able to fix it in place rigidly so the cable actuator would work.)

1. YES.

2. I would replace the head, guesing its cracked based on your posted details. I assume no water in the oil?

3. www.Radiatorbarn.com , be sure and get an all metal copper/brass radiator. 100 (2 row) to $150 (3 row) delivered IIRC.

Couldn't you just use a much simpler 2-way heater valve?

I'm sure there are ones made of brass or such and that are still vacuum operated.

Just another suggestion to throw out there.

5-90 said:

A bit, but not much. I've been thinking about a cable-operated shutoff myself, but haven't gotten around to it yet. (I could build it into the next rev of my copper heater lines, so it would be - natch - brass, and I'd be able to fix it in place rigidly so the cable actuator would work.)

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I have used a plane brass ball valve many times over the last 25 years. Sometimes I add a globe valve for throttling flow too. Both require poping the hood to operate.

Ecomike said:

I have used a plane brass ball valve many times over the last 25 years. Sometimes I add a globe valve for throttling flow too. Both require poping the hood to operate.

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I know - that's why I'm thinking a cable-operated ball valve.