Keeping the cooling system full

Anyone improved on the radiator fill system?

I have not had good luck keeping the radiator and water system full and bubble free. I do have a bleed screw on top of the thermostat housing (highest point of the system). But I have to put a plastic tube in the radiator fill port and fill it 9 inches or so above the radiator port til water comes out the bleed screw. either that or I jack the front end up to get the radiator cap level with the bleed screw. That has sort of worked til now but I have been seeing the temps vary somewhat while driving easily in the hills in 65F ambient temps. And if I stop for even 4 minutes, the temp goes to 200F and holds there only if I turn the fan on. And it bothers me that I'm only bleeding 1/2 the system since with the radiator cap off, I can't have the system running and warm with the thermostat open above 180F.

I took it to a custom performance shop and they couldn't find anything obviously wrong. They concluded I'm just not completely filling the system which is what I was leaning toward. So they are putting in a fill port and radiator cap off the thermostat housing and putting in a higher pressure cap on the radiator to keep it sealed under normal operating condtions. This essentially makes the new fill port the highest point and allows me to warm it up so that the thermostat opens and water circulates while I fill it.

I'm probably premature in posting this since I'm picking it up tomorrow. But I thought I'd share my thoughts in case someone else is sifting thru the same dilemma. I'll let you know how this experiment turns out.

I had this same problem on my 3.8 SC Stalker. I called Glenn Minehart and he said that I needed to "burp" the system with hot/cool cycles while insuring that I did not introduce more air into the system. Since you will have a new high point, as the coolant is cooling in each "burp" cycle, make sure that no air is re-introduced back into the system. It took me 4 cycles before I "burped" all of the air out of the system and kept adding a significant amount of coolant to my overflow canister to replace all of the air that was in the system. I used my overflow canister as my method of introducing more coolant and watched the rising coolant levels in the canister "burp". Glenn said it could have conceivably taken up to 6 "burp" cycles to get all of the air out. I guess I was luckier than some?

I used to have this problem. I had the exact same symptoms where even after multiple attempts at bleed the coolant system I still had trapped air and my temperatures would rise.

I even tried to use a lift to bring the car ass in the air to get the engine above the radiator so I could bleed it. Nothing worked.

And then I found this:
https://www.amazon.com/OEMTOOLS-87009-No-Spill-Coolant-Filling/dp/B01A2CQSU6

You simply fill the top reservoir, crack the bleed valve. The car bleeds in under a minute. Close the valve, close the reservoir, remove it. On goes the radiator cap and you are good to go.

I’ve used this 4 Times so far and each time the car is perfectly bleed. Temps stick at 180 all day.

Look into the old forum files. They've got lots of wonderful information gathered over years and this subject has come up several times. Burping was the original method, and it frustrated me, too. There are at least two others, but first consider this because it also contributed to my problem. Air cannot get out of the block if the thermostat is sealed when closed. I saw a thermostat that had a little hole in the disk with a little cotter key in it. I drilled a little hole in mine, and it works. Air bubbles up through that and lets water fill the block. You do that after you've got all the water in that you easily can after checking to see if it's really full. You can top it off easily with a turkey baster squirting into the (removed) air bleed hole in the thermostat housing. That sounds slow and tedious, but it didn't take 15 minutes. The engine is a little slow to warm up because of the bypass, so keep that hole as small as you can.

However, even better than the baster is to leave the air bleed open and with the engine cold, fill the overflow tank, then wrap a rag around an air gun nozzle and stick that "sealed" combination into the overflow tank filler opening. Set the compressor for low pressure so you don't blow up the reservoir, and use the air to gently push fluid back past the radiator cap and up through the engine. Refill as necessary. I was skeptical but game to try, and delighted at how well it works.

Also, it sounds like you're using a 180 thermostat. Don't. The engine and computer are designed to run with a 195. With a 13 psi cap, 195, and 50% antifreeze you're safe though it cycles between 195 and 215 on my gage. And if your radiator has the fan thermostat switch at the bottom, use that to control the fan. It works fine. It's got to be wired on the ground side of the fan. But if anyone needs it, I've still got an electronic PWM fan controller, new and unused because I got it before I realized I could use the Hyundai switch. $50 to a good home.

Jim


Jim Wallace
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Thank you gentlemen, all good info. Glad to know that this has been addressed and solved in more than one way. A couple of quick questions (more to follow I'm sure)

RE: The recommendation to stay with the stock 195 thermostat; is that because the car simply performs better with the stock computer? and seeing temps of 215-220 for 30 minutes on track (when I'm told the fans are supposed to come on in normal driving) is just fine? I come from a road racing background and we didn't like anything much over 200-210 on extreme 90-100F days and normally saw 190-195 on average 80-85 days. (however, that was a rotary, so maybe heat is more of a problem for a rotary than a recip motor?). And what if I had a race shop re-program the computer for a 180 thermostat and high RPM track conditions. Would that be a good idea and if not, why not?

Operating pressure: the new fill port by the thermostat has an 18# cap and a 25# cap on the radiator. I'm not sure I know what the problem is with higher pressures for track conditions I'm targeting.

As for the thermostat having a small hole to allow some small amount of circulation while cold, isn't that standard? In my limited experience, I thought it was for all thermostats and thought I saw one on the 180 thermostat I put in.

BTW, I'm a bit surprised and very pleased to see 3 knowledgeable responses. Thanks for the help.

Here's a few takeaways that I learned over the past few days.

1. a fully filled and burped system is absolutely essential in any weather, hot or cold. Means and methods of filling have to be understood and adhered to.

2. Adding a fill port by the thermostat makes filling much simpler. even so, the No-Spill funnel kit is a god send if not absolutely essential. It's endorsed wholeheartedly by my mechanic, a project car kinda guy.

3. The thermostat temp (180 or 195) is pretty much irrelevant to the overall cooling system function since (as I should have realized sooner) either one is wide open when at the recommended operating temps of 200-210. So, no need for a 180 since, as Jim Wallace says above, the lump actually likes it a little warmer (195+).

4. the small hole is not standard in a thermostat; recommend drilling one yourself.

5. Last and most important for me: track temps of 215 are just fine and if it goes higher to 230, no biggie; that's still not likely to be damaging. But Scott assures me that a full and fully functional system should not exceed 215 in any track condition.

Over and out on this issue.

That funnel really is great. Glad I could help.