Original Plastic Coolant Tank

[sdg3205]

Are these things really the time bombs we think they are? Is it always just a matter of time until they blow up or is it only a risk if the car overheats?

I really like the look of them.

[PB Co]

Are these things really the time bombs we think they are? Is it always just a matter of time until they blow up or is it only a risk if the car overheats?

I really like the look of them.

If a previous owner hadn't gone with an aluminum tank I would ride with the plastic. From reading around here it seems the consensus is if you melt your plastic tank you already had bigger problems.

I'd love to see a metal tank shaped like the plastic version with hemisphere ends.

[AugustneverEnds]

I've been running with one for the two years I've owned 10287. Probably gone 4,000 miles with it personally. The PO had the car for 9 years with the plastic tank. And I have driven on 90F days and in traffic without a problem thus far. The rest of my cooling system(water pump, radiator, thermostat, hoses, otterstat) are new though. Big like for being able to see the coolant level and not have to wait for everything to cool down. :cool1:

[hmcelraft]

The OEM coolant bottles can be a problem. Virtually all of the tanks that I have seen that failed, break on the bottom, in the middle, along the seam. In the "old days" when I lived in Houston (long before DMCH and the local dealers ran out of $35 new ones), we put two 5 inch (I think it was 5 inch) hose clamps, like the fuel pump bands, around the middle of the tank spaced about 1-2 inches apart to reinforce them. Never had a problem if you did that. After many years of use however, the bottles seemed to get extremely brittle, evidenced by numerous little cracks near the back, and appeared to be deteriorating. So, they will not last forever it seems. I went to stainless after 3 plastic bottles simply because OEMs were too hard to find in any kind of shape to use or, unused enough to be show ready and too pricey.

The plastic bottles were of course the easy way to read coolant levels. However, one thing that irritated me was the bleeder line location just below the cap. On some plastic tanks the circulating coolant would spray enough to leak out when the cap vented. There would often be a few drops of coolant on the ground from the venting after I stopped. The stainless tank I have now with the bleeder return positioned to the side of the cap and on the tank does not cause that.

I have seen all sorts of bottles to replace the plastic ones. There was one from some model of BMW that an owner put on that seemed to work well. I've seen some aluminum tanks that were shaped similar to the OEM and some that were shaped like most of the stainless tanks today. I have an aluminum one with an OEM look that has a clear plastic hose fit on the tank with connections to show the coolant level. I've never been brave enough to put it on - it looks nice but, I could never get comfortable with the clear plastic hose. Seems like a weak spot. I have 3 of the OEM plastic bottles - all well used - that were working well when I took them off. One is in good enough shape to be put back in service if ever needed - with the clamps of course.

[David T]

Are these things really the time bombs we think they are? Is it always just a matter of time until they blow up or is it only a risk if the car overheats?

I really like the look of them.


The plastic tanks were never meant to last this long. The plastic gets brittle over time and eventually will crack. When you lose the header tank you risk cooking the motor and blowing the head gaskets and that is a big deal. Same for the original plastic tanked radiator. 30 years is a long time to be using it. Age at this point is more important than mileage. For reliability's sake you should replace them.

[DMCMW Dave]

They work just fine. Until they don't. If you never drive out of town and don't mind the inconvenience of the occasional tow, go for it. It's like insurance.

If the bottle (or any part of a not-quite-maintained cooling system for that matter) lets go at interstate highway speeds, you'll generally blow a head gasket before you can get the car safely stopped.

[sdg3205]

Stainless it is.

[jwrayth]

Unless you buy from DMCEU (http://www.delorean.eu/catalog/product_info.php?cPath=19_24_41&products_id=41037&osCsid=hdhh2sorf22qst6mg68sas0fm4)

[sdg3205]

Unless you buy from DMCEU (http://www.delorean.eu/catalog/product_info.php?cPath=19_24_41&products_id=41037&osCsid=hdhh2sorf22qst6mg68sas0fm4)

So THATS where I saw it! Thank you.

That's under $120 Canadian. I'll look into shipping and see what it would cost. Are these of better quality than original plastic?

[jwrayth]

Unfortunately I can't help there; my car came with a stainless header tank. I've been considering switching to this one, but looks like I need a new radiator first...

[Patrick C]

Unless you buy from DMCEU (http://www.delorean.eu/catalog/product_info.php?cPath=19_24_41&products_id=41037&osCsid=hdhh2sorf22qst6mg68sas0fm4)

I may be wrong, but didn't DMCH try selling these new ones and they too were having failures splitting at the seam?

[mburshtain]

Any recommendation for a non plastic coolant tank?

[sdg3205]

Any recommendation for a non plastic coolant tank?

Any stainless tank from DMC, DPI or Special T is the "go to" tank.

[LordFly]

Mine had an UGLY steel one when I got the car. I replaced it with a stock plastic one. Been holding fine for a little over a year and probably close to 10,000km. Hell, I still have an original rad with plastic end tanks. I like to live dangerously.

[PB Co]

What material has the most desirable properties? Aluminum can cool quicker than stainless but the coolant itself is corrosive to aluminum. I removed some crust around the lip where the cap gasket seats from my own. I don't think a stainless tank would have had this issue.

I like the look of plastic because it's oem. These metal tanks remind me of hot rods or go cart gas-tanks. It is good to know there is still a new plastic option out there but I'm not going back.

[Rich]

What material has the most desirable properties? Aluminum can cool quicker than stainless but the coolant itself is corrosive to aluminum. I removed some crust.....

Most modern coolants are OK for aluminum, right? - unless they are not renewed/replaced regularly, which perhaps led to the "crust"? Aged-out coolant can corrode any of the aluminum bits like the coolant tubes to-fm the radiator, the heater core and most of the engine, setting aside wall thickness for the moment.

This means SS or aluminum are OK for that tank, no?

[dn010]

I still have my plastic header bottle....hanging on my peg board in my garage. I went stainless many years ago.

I never bought coolant that didn't say "safe in aluminum engines" or something similar. These past few years, I now use Zerek Dex-Cool which doesn't say it on the bottle but states it on the Valvoline website that it protects "ALL" cooling system metals including aluminum. I use it in my truck too (which also has an aluminum block), I really like that product but is more expensive than traditional auto-store coolants.

[Soundkillr]

I may be wrong, but didn't DMCH try selling these new ones and they too were having failures splitting at the seam?

This is true. They were actually splitting at the neck, where the cap goes. The bottle itself was fine, it was the material used for the filler neck that was splitting. Shame to, I bought one, and it lasted 60 miles. I was bummed. Now I'm stuck with a metal one. I'm one of those that can't stand the look of anything other than the original plastic....

[Jonathan]

Dave, if you want a plastic one, let me know. I still have the one that came with my car when I put the SS one in. It wasn't split or leaking, I just replaced it along the "cheap insurance" justification lines. Shipping within Canada and no customs might lower your costs.

[sdg3205]

I talked to Ed and he said the first batch was bad but this is now a new run with a 1 yr warranty.

[NightFlyer]

This is a subject near and dear to my heart, as someone who has taken a lot of shit for continuing to run a plastic bottle on a concours car of historical significance :biggrin:

IMHO, there are three factors to consider when running a plastic coolant header bottle:

1) making sure that the temp / pressure of the coolant within the bottle never exceeded the design limitations of the plastic used in construction of the bottle;

2) making sure that the freezing point of the coolant within the bottle was always rated below the experienced ambient temperatures of the environment in which the car finds itself in; and

3) making sure that the bottle wasn't exposed to improper long term outdoor storage (exposure to ozone, UV, IR, and extreme swings in humidity will wear on plastics in a similar fashion to how they wear on rubber components).

If you do these three things (and can verify that they've always been religiously adhered to throughout the life of the bottle/car), I'd personally be extremely confident in running the plastic coolant header bottle indefinitely into the future, and wouldn't have any reservations about doing so.

If you can't accurately verify the historical experiences of the bottle though, then switching to a metal bottle is indeed cheap insurance against a potential future failure.

So, there's my two cents, for whatever they're worth...