Cooling system overhaul

[aevansgatech]

I'll be receiving most parts for overhauling the cooling and heater system tomorrow and I'm hoping to get a couple tips and tricks in advance! I have a new radiator coming (not Al unfortunately), all new radiator hoses, a heater core valve, and fan switch (harness). Keep in mind this is my first foray into real restoration and repairs so I may overlook some simple things

I saw these comments from lglade and was wondering if I should expect to have to modify the parts I just ordered. I did not order the tube as of yet.
A couple bits of advice:
1. Since the new valves have a different departure angle from the original 124 parts, go ahead and buy the new replacement heater tube with the correct departure angle. It will save you a lot of grief during re-installation.
2. The bolts on my new core were slightly further apart than the holes in my new valve (go figure), so I had to oversize the holes in the valve to get the parts to fit up. No big deal, but an added step that I did not anticipate.


Aside from that, I think I'm good to go. The old (leaking) radiator is fully drained and ready to remove.

[KevAndAndi]

What is it that you are addressing with regard to the heater core? Was the valve leaking? Are you not replacing the heater core?

I plan to address some of these things in the near future. My rad is not leaking, but it is original and I'd rather be proactive. I'm looking at Mark Allison's aluminum rad. I'm also considering replacing the (ancient) heater core, (slightly leaky) valve, and (rusty) tubes, but it's questionable as to whether it is worth it for me, as the car is not driven in the cold. I bypassed the heater core to avoid problems.

Please keep us apprised as to your progress.

[baltobernie]

A new metal heater tube is the clean way to go. Here's the kluge way: http://dcfiats.org/tech/Spider_heater-A.pdf
Did you remember to get a new flushing tee (if you don't have one installed already)?
If you're replacing the items mentioned to cure some kind of overheating problem, a new thermostat would also be suggested.
I'd consider a DIY chemical flush with all the old items in place before disassembly.
If you're going to remove radiator hoses and shroud, why not replace the timing belt, too.

[geoff]

I have just gone through some of this process - new rad, stat, etc.
Having seen the terrible corrosion of the alu around the stat and the temp sensor housing, i have used Evans waterless coolant instead of water+antifreeze. I am pleased so far - and would recommend this to anyone with aluminium engines.
The engine is difficult to bleed - but i guess you know that already. It took me three or four times to get it right - and i had to be careful each time not to loose my very expensive coolant!
regards
geoff

[aevansgatech]

Thanks for all the tips guys.

Here's the reasoning behind the repairs: Heater core valve started gushing coolant into the footwell on the last drive of the season The heater core itself isn't leaking so I have opted not to buy a replacement. The radiator has been leaking, but just slightly, since I got the vehicle. It doesn't overheat or anything though, so I'm only replacing the radiator and hoses as a precaution (age) and to stop the leak.

I think my next steps would be to buy that flexible NAPA hose to accommodate the slightly different new valve geometry.

As for the flushing procedure, I only drained what was in the radiator. Can anyone post a good picture of where the engine drain port is? I honestly couldn't find it in the manuals or searching. As of now, the radiator sits empty, but there is probably residual coolant in the engine.

[baltobernie]

On the 1800, it is the brass plug below the #2 freeze plug (counting from the front). Other engines have an actual thumb wheel, but in the same general position, under the exhaust manifold.

Hey, I forgot to connect my heater pipe strap when I replaced the head gasket

[So Cal Mark]

flex hoses are a temporary solution, they don't last very long

[baltobernie]

The hose I suggest is molded, and should last as long as the one on the other end of the core. No question though, a stainless pipe is the better solution.

[aevansgatech]

Thanks guys, once I'm in there I'll inspect the heater pipes. I don't suspect any issue with those other than the new valve not aligning with the old pipe.

If I end up using the flex hose, do you need to cut and leave a part of the pipe to slip it over and clamp on? Otherwise there's nothing on the heater core valve to clamp the hose to

[baltobernie]

http://dcfiats.org/tech/Spider_heater-A.pdf

[KevAndAndi]

Here's the reasoning behind the repairs: Heater core valve started gushing coolant into the footwell on the last drive of the season

Yikes. One of my worst fears. That's one reason why I bypassed the heater core.

The heater core itself isn't leaking so I have opted not to buy a replacement.

I have heard others say that once you start monkeying with the heater core's valve, etc., you can compromise the old core and potentially cause leaks. Just a caveat.

I think my next steps would be to buy that flexible NAPA hose to accommodate the slightly different new valve geometry.

I would go with stainless steel in the new geometry.

As for the flushing procedure, I only drained what was in the radiator. Can anyone post a good picture of where the engine drain port is? I honestly couldn't find it in the manuals or searching. As of now, the radiator sits empty, but there is probably residual coolant in the engine.

I'm pretty sure I found a good picture on this forum. If you have a flush T and you backflush the system, you should be able to get all the old coolant out without opening the engine drain port. Personally, I was afraid to open it for fear of stripping or breaking something and not being able to get it back on.

[baltobernie]

If you have a flush T and you backflush the system, you should be able to get all the old coolant out without opening the engine drain port. Personally, I was afraid to open it for fear of stripping or breaking something and not being able to get it back on.

The block holds quite a bit of water. Draining it is necessary to completely evacuate the system. Then one can fill with the correct 50/50 mixture.

Without draining the block, you must add nearly 100% antifreeze/coolant to reach the desired concentration. But then you have city or well water instead of distilled water; not optimal.

[aevansgatech]

So today I tackled the radiator and hoses. I was pleased with how smoothly it all went together and as a bonus the new radiator-to-thermostat hose doesn't rub on the timing belt cover anymore.



I do think I have a better idea of the heater system now though and it looks like the PO already put in the bleed valve for me

[baltobernie]

... and as a bonus the new radiator-to-thermostat hose doesn't rub on the timing belt cover anymore.

Yeah, a lot of folks have struggled with parts suppliers over the years. Many things sold for our cars were cobbled from other sources. A (in)famous one was a section cut from radiator hose sold as a Spider fuel filler hose. Ethanol, of course, destroys hoses not specifically formulated for such use. What a spot for a massive fuel leak!

[aevansgatech]

So my heater pipes are in good shape, but I'll eventually order the stainless short pipe for a proper valve install

I did notice, however, that the short hose (supply pipe to short heater pipe) is pretty much bent and pinched off. I'm guessing that is restricting coolant flow to the heater core and maybe led to my valve failure?