Radiator caps
 

Guys

Are there good and bad branded radiator caps out there?

If so what is a good brand and one I should be targeting?

I'm not so sure that my current cap is sealing well as I think I am getting a slow loss of coolant over time and wonder if a poor sealing cap is the culprit.

Any feedback would be great.

Thanks in advance.

Steve

Try a stant lever cap if you can find one. They are available in different psi ratings if required - https://www.pwr.com.au/portfolio/radiator-caps

Very hard to go past Stant caps

Steve,

I agree with the above. I have always used Stant caps on all of my cars. Do you have an overflow catch can? If not you could be losing small amounts out the overflow on your radiator neck.

Ron

Steve,

I just completed several cooling system upgrades and also went with a Stant cap. I spent a couple more bucks for their Performance series cap (with lever). The Performance series offered the following benefit as described on Summit's site (for my part 18330), which made sense to get if it really does that:

"Stant Performance Lev-R-Vent radiator caps feature a more precise pressure valve that has a 25 to 50 percent narrower range of pressure than those on standard OEM or aftermarket caps. These caps feature a Lev-R-Vent, which harmlessly vents pressure through the overflow tube before you remove the caps."

As far as a possible sealing issue, there are several threads discussing shape/condition of mating surface you may want to verify for tips. Also, if using any silicone hose, during my research it appeared those allow some evaporation to happen (have pros/cons).

I have a expansion/recovery tank and an overflow tank. With those, you may find excess in the overflow tank, obviously. Also, if the expansion/recovery tank is filled over the fill line (mine a brass inner baffle about half way up to fill to). If overfilled, upon expansion it will overflow, whether to an overflow tank or to atmoshpere, however you have it setup. If that's the case, you may find if set to the proper (lower) fill level, then you may experience no such loss.

By the way, while I changed many variables on mine and can't isolate improvements to the cap per se, my system is working very well now, and the cap seems to be doing its job just fine.

Best of luck with it. Brent

I like using a radiator cap with a zinc sacrificial anode. racewayparts.com product number Z17700 16 lbs. cap for $34.55. What sold me was the first time, I took off the cap and saw all the salts and dissolved anode. I use nothing but distilled water and antifreeze but remember all the different metals in your system can cause an electrical charge in your coolent even with a grounded system.

Bill K

So I look up Stant and a seller in OZ and PWR come up great.

$29 for the cap (if collected from the Qld office) and they want $49.50 for postage. They must all wear balaclavas to work me thinks...

For a small item an AP bagged item would be maybe $12 - $15 postage, so they are rip off merchants.

Any Victorian sellers anyone knows of?

Slowly - try eBay - a quick search turned up a couple of suppliers with stock, one in Fairfield and one in Dandenong. Might be worth sending them a message on eBay and seeing if you can drive down and pick one up.

If you can wait - they are like $6 on summit plus shipping!

Steve,

Well you're probably well ahead on this, mentioning just in case. There are one way (non-recovery) and two way (recovery) caps, depending how your system is designed. The two way have the upper and lower rubber gasket/seal. Also, you likely know, but the pressure rating is important for the application. If too low a rating for example, it would release earlier than otherwise designed and perhaps a reason for losing fluid prior. Lots of cap difference/feature information on web searches if needed. Brent

Thanks guys

Ebay was no use as the model I want is only currently available from OS providers, so Summit it was.

A $7 part with $30 freight, all USD of course, but still cheaper than the Queensland option.

I could have asked for help locally purchasing and sending more normal Ozpost but that would still only have been $20 cheaper in total.

I can wait a week and the hardest part was dragging my credit card out of the wallet.

So thanks all.

It also led to discovering my radiator's rated pressure, fortunately about the same as the current cap's rating of about 16 - 17 PSI.

The Stant 16 PSI lever model fits that bill well.

We will see what difference this makes over time.

Cheers Chaps

At the company I retired from, we used to go over the revenue numbers at monthly staff meetings. One of the line items was 'Freight Revenue', LOL.