Coolant

[Parzival]

Thanks for this. Yes the return line is very close to water line but I have emptied a bit. Come to think of it the bubbles are worse after is emptied some so maybe you are onto something as it’s probably stirring up even more. I was getting a very small amount of overflow when the reservoir half or more full but now it’s only 1/4 it is not overflowing at all or loosing any coolant (or overheating). I’m also wondering if there is a bit of contaminant in the coolant (as it was recently changed) that might exacerbate the bubbles (it is really a kids bubble bath in there not just a few here and there).

If you are getting foam like soapy water, you may have a contaminant that has amended the surface tension of the coolant (Like adding dish soap to water) Giving it the ability to hold bubblers of air.
My coolant bottle has been at half full for a 1000 miles, over flow tube is bone dry after even the longest drives in mid Florida summer. My temperature gage fluctuates between the 1/4th mark, and about half way between that and the 220 mark.

[cdrusn]

I hate to disturb the boo birds but I would never use the "green stuff" coolant. There are so many improved antifreeze products why not use them. I use Zerex 05 in my
1988 Mercedes 560SL, all aluminum engine. I currently use Dexcool in my 1984 Porsche 928 but will shift to Zerex when I get around to it. I run Dexcool in my Delorean.
I had a friend that used the green stuff in his 450SL mercedes but he never changed it every 2 years as recommended. He asked me to look at it when it wouldn't start. When I pulled a plug to run a compression test it shot out green antifreeze that had eaten quarter size holes in the heads because of delectric corrosion (steel and aluminum plus water equals an electrical charge that eats metal). Dexcool and Zerex last at least 10 years between flushes. Also use distilled water from the grocery store.

[David T]

Use what you want but the Delorean was designed for the green stuff. In any car, if you don't test and change it when you are supposed to, you will get all kinds of problems and newer cars are very fussy about what kind of stuff and how often to change it. The newer coolants can't be mixed with other kinds of coolants and have very strict conditions as to how often to test and change besides some of them are VERY expensive. There is no particular advantage to using these "exotic" coolants in a Delorean so why would you want to? Use the green stuff, test it every year and flush it out and refill every 5 years with 50/50 concentrate and soft water. If the water in your area is "hard", by the pre-mixed stuff so you don't have to add water.

[cdrusn]

The recommended change for conventional or "green" antifreeze is every 1 to 2 years. The manufacturer, Prestone, recommends every 2 years. Most "exotic" antifreeze can
be changed at 5 years or even longer. It's just a matter of chemistry. Deloreans were built 40 years ago when antifreeze was all green, that's why they used it. All expensive European and most expensive domestic cars (i.e. Corvette) uses Dexcool or Zerex 05. Corrosion from not changing the green stuff can show up in the radiator, the water pump, sensors, etc. and cause overheating. I don't drive my Delorean much so why would I want to change the coolant every 2 years with just 200 miles or so on it? If I wanted to keep my Delorean like it was built 40 years ago I wouldn't be using Mobil 1 oil, new rubber belts, improved shocks, etc. We need to keep our cars maintained in the 2020s not the 1980s.

[David T]

I have many cars and work on many cars that use the green stuff and 5 years is easy to do if you test every year. Never had a problem unless it got mixed with something like Dexcool or by mistake someone puts plain water in or windshield washer fluid or I have seen brake fluid too. While there are many things that are technologically advanced over what was available in the 80's, Prestone is still a good choice for a permanent type anti-freeze for a Delorean.

[Jonty]

Hi all

Well today I just noticed a very small pinhole or crack beside the bleed screw on my thermostat cover. Very weird but I wonder if this would be enough to add all the air in seeing to the coolant?

[Bitsyncmaster]

Hi all

Well today I just noticed a very small pinhole or crack beside the bleed screw on my thermostat cover. Very weird but I wonder if this would be enough to add all the air in seeing to the coolant?

That doesn't look like a stock bleeder. If you buy a new cap, get a new bleeder also. I bet it's the wrong thread and the PO over tightened it.

[Jonty]

That doesn't look like a stock bleeder. If you buy a new cap, get a new bleeder also. I bet it's the wrong thread and the PO over tightened it.

Thanks I never noticed that. I bet your right. I have a Toby self bleeder system coming so that will swap out for the wrong bleed screw.

[Jonty]

Actually I think the bleed screw is the same as supplied with the DGo water pump

[David T]

Looks like someone installed a reducing bushing and stuck a bleeder screw into that. If they forced it, by over tightening or wrong thread it could have cracked the housing. Replace the housing and get the correct bleeder screw.