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Painting the stock coolant bottle

30 April 2004
Olathe, KS
Dear NSX owners,

I purchased a couple of cans of charcoal gray spray paint specifically for bumpers from a tool store that is basically a liquidation center. I then purchased some plastic primer from the local hardware store. I removed my coolant bottle, taped over the openings, sanded it down with 400 grit sandpaper (according to the directions on this site), applied the primer, let it dry overnight. The next day, I started to spray the bumper paint, the paint immediately started to wrinkle. After letting it set a few minutes, the bottle looked horrible, all wrinkled over. I then took the garden hose and a brillo pad to the bottle and got all of the paint and primer removed. I have since re-installed the coolant bottle still unpainted. I figure the paint I got from the tool store was bad. To everyone who has done this procedure before successfully, what specific brand and type of paint did you use? The site mentions Plastic Bumper & Grill Restoring Spray # 20241 from Griot's Garage. I called them, they no longer carry this item. Any suggestions? Thanks.

'91 Red/Ivory
Re: The "revolutionary paint for plastic"!

Ojas said:
John, I used Krylon Fusion. It was inexpensive and, so far, has held up well.

Cool. That's what I'm about to do.... :cool:

Did you mask off a stripe so you can see the coolant level?
I was just about to recommend a minor preventive maintenance tip for these tanks. Seems that with age they tend to fail at the seam and you'll end up having to buy a new one or get one of the aftermarket varieties out there. I found that if I mixed some JB Weld together and filled the seam with it, this should go a long way in preventing a leak from this area. Once the JB Weld is cured, you can sand it to look pretty and then do your painting just like before. Worked for me so far. Good luck.
Hey guys,

I purchased the Krylon Fusion paint and applied it to the bottle, it bonds great and the bottle looks beautiful. I re-installed the bottle, the engine compartment looks 100% better. Thanks again for the great advise. This site and its members are priceless!!!!

'91 Red/Ivory
Re: The "revolutionary paint for plastic"!

Ojas said:
John, I used Krylon Fusion. It was inexpensive and, so far, has held up well.

Posted the same on the Krylon Fusion specifif thread.


I just checked with Krylon. They do NOT recommend the use of Krylon Fusion for such application as it is not made to withstand the heat levels in the engine bay or from the radiator (which can reach 200+F).

I may check into Duplicolor's engine paint applications or finish what left over paint I have in FoliaTec.
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I used SEM atomotive trim black on mine in April. It turned out great and has held up very well to date (4k miles clocked since painted).
Is sanding and priming a must? can't it just be sprayed with some high heat black or something? I gotta do something with mine. Its going to be hideous under my mesh engine cover.
Be sure to clean the tank thoroughly and then do a light sanding with a fine grit sandpaper (I used about a 400-500 grit). I also preppped it with SEM plastic prep before painting. For auto trim/bumper paints priming usually isn't necessary for a job like this.
I painted my bottle with flat black Krylon Fusion as well. I simply cleaned the bottle thoroughly and sprayed, no other prep work required. A couple months and track events later, it still looks as fresh as the day I painted it.
got ethylene glycol?

Seems like Krylon is the most cost-effective AND best performer of the acrylic-based spray paints used on the 'jugs. I used a bumper/molding/trim spray-paint after a very quick bottle-wipeup w/ a dry-cloth and 600grit sanding. I used 3 coats, the results are acceptable but far from "engine dress-up." I didn't feel like doing a high-temp' clear-coat application in the end, as I had planned on doing so in the beginning.

(plugging/taping the bottle's spout-openings & cap, clamping the hoses, applying multiple coats of paint... more involved DIY than initially presumed)

Three things I'd recommend:

- extra 6x16 flange bolts or zip-ties in'case you drop one of the OEM ones and can't retrieve it!

- 1000grit sandpaper or steel-wool... otherwise noticable scratches will show through the paint!

- if/when the coolant-reservoir fails, Dali's "ChemFilm Finish COOLant Tank" for $158 is an decent option... COOLant Tank (includes cap, usually $15-$25 for aftermarket)
It has been a little over a year since I painted my coolant bottle with the Krylon Fusion paint. It still looks as good as when I first did it, no peeling or cracking. I also used the same brand paint for my injector and coil covers last spring, no issues at all!!

'91 Red/Ivory
Interestingly, when I sent an e-mail to Krylon re Fusion, this time they said it should be OK compared to the phone response yesterday when they said no. Well, I sent another inquiry specifically asking if they would recommend it if the water temp hits 200F. Will see what they reply.

For those who have applied it, do you track your cars or mostly garage queens LOL!

After seeing this offered by DaliRacing, I am wondering why bother painting the OEM coolant tank!!
OK, here is the update. Use the info as you see fit. Offered in the sequence of responses. HTH. YMMV.

Q 1: I would like to paint the radiator water overflow coolant bottle which is
hard plastic like PVC. Since the temps can get pretty high in the engine
compartment, and the bottle from radiator overflow, what product would you
recommend to (a) prime if necessary; and (b) paint.

Customer service said Krylon Fusion would not stand such heat.

A 1: Thank you for taking the time to contact us. In general the coolant
return bottle is made of a thick plastic, and the outside of it does not
get that warm. The Fusion should work for this application without a
problem, as long as the surface is cleaned and prepared properly. Run the
car at normal operating temperatures and feel the outside of the bottle.
If the surface is not too hot to touch, the Fusion will be OK. Please let
me know.

Have a great day.

Q 2: Thank you for the response.

We know that the oil temps can get into the 260F on hard driving, and many
of us are seeing water temps near 200F when we take the car to high
performance driving schools (not racing) on the track. The Fusion states do
not exceed something like 90C which would be equivalent to 194F. Of course
that doesn't mean the plastic will get to that temp.

A 2: The Fusion should not exceed temperatures above 120 degrees Fahrenheit.
You can use the Engine Enamel for this application as long as you prepare
the surface properly. Allow the paint to cure out a full 5 days prior to
putting it to the test.

Q 3: Another question. Does Krylon carry "wrinkled" look paint spray (in red or black) for use on the hard plastic described below? Fusion or other

A 3: Krylon does produce a Black Wrinkle Paint (3370) which can tolerate
temperatures up to 250 degrees Fahrenheit. It is not necessarily intended
to be used on plastic, but may work for this application as long as the
surface is scuffed and thoroughly cleaned.
Just an update regarding coolant tank temps at the track. At Infineon last Friday, with ambient temp in the low 70sF, the coolant tank was reading 187F in the paddock using an infra red gun.

So the wrinkle paint should be fine, but Fusion will be borderline at best.