GTE Radiator caps

Rudy van Daalen Wetters · Mon Mar 15, 2004 5:07 pm

Can anyone suggest a radiator cap for the GTE? Mine is incorrect and looks like it belongs on a Fiat 600. Also, what pressure rating is recommended?

Thanks,

Rudy van Daalen Wetters s/n 4001

Post by **tyang** » Mon Mar 15, 2004 8:47 pm

Hi Rudy,

The original caps are hard to come by, and if you find one it, will usually need to be nickel plated, and the accuracy of the pressure will be suspect.

As far as what pressure to run, first understand the reasons for higher pressures. The higher the pressure, the higher the boil over temperature, but too high of a pressure, and you risk blowing hoses, and weak solder joints. I'm starting with a 7lb cap and it should bring the boiling temperature up over 100 C. If I need more temp, I'll go to a higher pressure cap, but I also understand the risks! I certainly don't want the heater core bursting, spilling antifreeze all over my carpets!

Tom

racertodd · Post by **racertodd** » Mon Mar 15, 2004 9:37 pm

tyang wrote: I'm starting with a 7lb cap and it should bring the boiling temperature up over 100 C.

100 degrees C?
Plain water boils at 100C (212F). A 50/50 mix of ethylene glycol (the good ol' green anitifreeze) and water boils at 106C (223F), a 70/30 mix boils at 113C (235F).
For each pound of pressure above atmospheric that the system is pressurized, add 1.6C (3F) to the boiling point of the coolant.
A 7lb cap adds 11C (21F) to the boiling point. So a 50/50 mix with this cap nets a boiling point of 117C (242F), with a 70/30 mix you get 124C (255F).

Todd

Rudy van Daalen Wetters · Mon Mar 15, 2004 10:15 pm

Thanks for the information guys. I may have read that the water pump seals may not be able to sustain the higher pressures of, say, a 13 pound cap or the like. I think it is smart to start with the seven pounder and do the 70/30 mix that was mentioned. My next question is if not the original cap, how would you find a good alternate that would work and seal correctly? Do I just trial and error a Stant cap? My current cap looks good but the inner seal does not even reach the bottom of the neck! I noticed this quite accidently as the coolant merely expanded into a resevoir tank as the car warmed up.

Rudy

Post by **tyang** » Tue Mar 16, 2004 12:22 am

Hi Todd,

I meant even with plain water, and I didn't have the exact temps with an antifreeze mix. Thanks for clarifying!

Tom

Michael Bayer · Post by **Michael Bayer** » Wed Mar 17, 2004 10:44 am

Guys: Two points: I always believed that a 75% water to 25% antifreeze improved the heat transfer rates of the coolant, increasing the heat exchange rates of the radiator, and the radiator cap for the later 330s is a lid only, with a free flow to and from the overflow tank where that tank cap (a traditional radiator cap) enables pressure and relief. Michael Bayer

Post by **tyang** » Wed Mar 17, 2004 12:27 pm

As with everything, it's a compromise. Water transfers the best heat when compared to antifreeze, but antifreeze has a higher boiling point, lower freezing point, and will resist ionic corrosion (I think that's the term) between dissimilar metals (aluminum, steel, and brass in the Ferrari)better than plain water. I personally use a mix of 50/50 for a good compromise.

Tom

Rudy van Daalen Wetters · Wed Mar 17, 2004 10:24 pm

Tom,

Would you know of a good substitute cap for the GTE if I find an original one for the time being?

Rudy s/n 4001

Post by **tyang** » Wed Mar 17, 2004 10:55 pm

Hi Rudy,

I think any 7lb cap would fit for now. To find a permanent cap, I would go to an old Foreign car shop in town and see if they have a stash of old radiator caps. If you're lucky, you'll find a "period" cap that won't need nickel plating.

Another thought is to use a reproduction cap for a 60s vintage car like a Mustang. It'll be wrong, but at least it'll look like it came from the right era!

Tom

Jim · Post by **Jim** » Thu Mar 18, 2004 12:50 am

Speaking of corrosion: I place a sacrificial Magnesium anode, suspended under the radiator cap, to prevent corrosion. Magnesium is the best material when protecting Aluminum.
Jim

JAshburne · Post by **JAshburne** » Thu Mar 18, 2004 2:21 am

tyang wrote:Hi Rudy,

I think any 7lb cap would fit for now. To find a permanent cap, I would go to an old Foreign car shop in town and see if they have a stash of old radiator caps. If you're lucky, you'll find a "period" cap that won't need nickel plating.

Another thought is to use a reproduction cap for a 60s vintage car like a Mustang. It'll be wrong, but at least it'll look like it came from the right era!

Tom

And at least the Mustang also has a horse emblem on it!

John

Michael Bayer · Post by **Michael Bayer** » Thu Mar 18, 2004 7:44 am

Tom: To help the cooling, but still preserve the engine, I find that 25% antifreeze and 75% water does markedly help cooling, not that 209s would ever tend to run warm!

Post by **tyang** » Thu Mar 18, 2004 8:52 am

Hi Guys,

Speaking of sacraficial anodes, here's an interesting item I found:
http://www.mustangsplus.com/Merchant2/m ... Code=07385
It looks kind of "period," and has the magesium anode already installed. They're probably 13lb caps though, but I think the Ferrari cooling system can handle the pressure.

Tom

Koll · Post by **Koll** » Fri Mar 19, 2004 9:50 pm

Jim wrote:Speaking of corrosion: I place a sacrificial Magnesium anode, suspended under the radiator cap, to prevent corrosion. Magnesium is the best material when protecting Aluminum.
Jim

Hi Jim,

How did you actually do that? Do you have any pictures?

Thanks!

Jim · Post by **Jim** » Sun Mar 21, 2004 3:12 pm

Dear Koll,

This is the sacrificial system I use in my 330 GTS:

I purchased the Radiator Saver (#74-7496) from the on-line catalogue of J C Whitney. This saver has a lead anode held by a bolt, wire, and a metal ring that sits in the neck of your radiator fill spout. The lead anode is no good for aluminum, so I discarded the lead, and used the rest of the system.

Now, the challenging part: I bought my magnesium anodes from a gentleman in colorado, but I think he was clearing out his garage. You should be able to have a metal shop make a magnesium anode for you. Use the lead anode as a template for its size. Note that the lead (and my magnesium) anode's bolt hole is threaded (3/32 "), but not necessary to have the thread, just so the 8/32 " bolt will slide through your anode hole.

One last pearl: I switched out the J C Whitney bolt, washers, and nut for stainless steel, as the stock hardware rusted, though the braided wire and radiator spout ring seem to be ok.

I recommend buying several of the Radiator Savers for back-up, and a good number of magnesium anodes, as they do sacrifice themselves fairly rapidly (maybe less than 6 mos), which means the're doing their job. The anode has to be in water and the radiator cannot be electrically isolated (just use a basic circuit continuity checker to confirm that your radiator is grounded (It most likey is). I still use modern antifreeze/anti-corrosion solution in my cooling system.

Sincerely,

Jim