'35 Large Top Tank Radiator
 

Ive an original '35 large top tank radiator on my '35.
Since I put skips rebuilt pumps on the engine and the three lbs. check valve the engine stays much cooler.We've not hit the summer heat where I live yet but I notice the engine temp. difference.
Im curious if others have had this similar situation happen to there radiator.
The system is completely full by instructions sent with the pumps.
The top tank top flexes considerably when heated up and when everything cools off it sucks the top of the tank down a lot more than when I used the original style pumps.
Before I used the check valve and the water level about an inch below the fill cap I ran the car down the road without the grill and hood on.While going about 45 down the road I watched right before my eyes the tank top suck down about an inch and a quarter.
Ive since put the check valve on and filled it all the way up. By expansion most of the crush has come out.
Any one else experience this? Has any one else come up with a solution to tank flex?

Re: '35 Large Top Tank Radiator
 

Rob, The '35 large and the 36 are seriously effected by pressurizing the system as you have done with the check valve. The seams in all the early radiators were not meant to withstand pressurization, however, most others are OK with 3 or 4 lbs. The large expanse of flat unsupported brass on top will flex in and out until eventually, a seam will give way.

I would advise allowing the coolant level to go down to just at the bottom of the filler neck to allow an air pocket for expansion. I would further advise that when your radiator is next removed for repair, to improvise a brass support brace to braze inside the top tank to prevent the flexing.

Re: '35 Large Top Tank Radiator
 

Replace the check v/v with a catch can, fill radiator to the brim and drive; it will always remain full, irrespective of temperature.

Re: '35 Large Top Tank Radiator
 

My mid year production '35 Fordor, that I drive most often, has the small top tank radiator, Haney WP's and his overflow check valve. I have no problems with tank flex (aka oil canning) with this radiator. So maybe switching to a small top tank radiator might be an option, but I always thought the large top tank radiators were an advantage because of having the additional coolant.

Re: '35 Large Top Tank Radiator
 

I agree on the more coolant part on the early radiators. Does ur rad. have an embossed B4 on the top tank and are the tubes angled or straight (front of rad. to fan side of rad.)? Also my cooling system with the large top tank holds just a touch over 5 gallons.What does yours hold? Thanks JM 35 Sedan

Re: '35 Large Top Tank Radiator
 

Rob, some pictures of two small tank '35 radiators so you can see how tubes look. They do have B4 on top tank. I'm guessing coolant capacity is about 2 qts. less with small tank vs. large tank. Will update post if I find the exact capacity. The small tank radiator requires longer firewall to top tank support rods. '36 went back to a large top tank configuration, most likely to get back the extra capacity.

Re: '35 Large Top Tank Radiator
 

Thanks a lot for the pics.Looks like I have one very similar that came with the car.When u look in the filler hole theres 4 rows of tubes and there slanted to the left on the first row then the second row is slanted to the right.Each row is staggard so as to not block the the row in front. / / / / / /
\ \ \ \ \ \
/ / / / / / Like that.
I like the fact the large tank holds more. I may give the smaller one a try.

Re: '35 Large Top Tank Radiator
 

Also in comparison of the two radiators. The large top tank one has 162 tubes where the small top rad only has 106. At least the ones I have anyhow.

Re: '35 Large Top Tank Radiator
 

Re: '35 Large Top Tank Radiator
 

Mike,
From where did your steam escape?

Re: '35 Large Top Tank Radiator
 

John-

Something I have noticed when comparing '35 small top radiators with '35 large top is the angle the hoses take to get to their respective radiator openings from the engine. The large top with its' down pointing outlets requires a slightly longer reach of the hoses. This longer reach creates a sharper angle that places the upper radiator hoses very close to the fan blades. If all goes correctly you have about 3/8" clearance. The smaller tank with its' "banana tube" openings extends farther away from the radiator and as result the radiator hoses coming from the engine are not at a sharp angle and thus avoid the fan blades with ease.

Now, my observations may differ from what others have found and this may not be necessarily the case for all '35 radiators as Ford was doing a LOT of experimentation with radiator size and shape to overcome testy cooling problems.

Tom

Re: '35 Large Top Tank Radiator
 

One of the misconceptions regarding the two types of radiators used on '35s is that the large tank version and was replaced by the small tank version as a running change. This is not borne out by Ford's engineering records. While accurate that the small tank version was adopted as a running change, it did not completely replace the large tank version, which continued to be used throughout the entire '35 model year.

The engineering releases specify that that the small tank radiators were to be used in the assembly plants that served the dealers in the northern part of the country, such as Chicago, Dearborn, and Twin Cities and that the large tank version at the assembly plants that served southern dealers such as Long Beach, Norfolk, and Cincinnati, which is further confirmation of the differing cooling capabilities of the two radiator designs.

Re: '35 Large Top Tank Radiator
 

Go with Brian , works with most any system. Too simple !!!

Re: '35 Large Top Tank Radiator
 

All very interesting point of view and info in general. DavidG, most interesting.Uve read this info in ford archives? Im very curious...

Re: '35 Large Top Tank Radiator
 

As for steam escape. When the top tank collapsed the first time I didn't have the 3 lb valve in.Also it never got hot enough to steam.

Re: '35 Large Top Tank Radiator
 

I have never seen or heard of the top tank sucking in an 1 1/2". You must have some strange problem. Did you add a large bottle of Barrs heavy duty aluminum or copper granular heavy duty stop leak as per Skips instructions? You could remove the check valve and put a rubber hose from the bottom of the over flow tube into a large plastic bottle sitting on the frame. Bring the hose into the top of the bottle, cut the end on a long angle and push it down to the bottom of the bottle this is so the hose don't get closed on the bottom. Put a hole in the bottle top and put a hose in an inch in that hole, this is just a vent and over flow incase the bottle fills up, and will release compression pressure if you have a compression leak. Here's how it works.
The back pressure from the restriction of the radiator tubes will force the water through the overflow tube and added hose into the bottom of the bottle containing water that would be lost from the over flow tube. All of the water lost will be contained in the bottle. As the engine cools when shut down and as the water temperature drops below 155 degrees it causes a vacuum in the engine this is when the upper radiator hoses can be sucked in but releases them as it gets cooler. As the temperature drops below 155 the vacuum also sucks the water from the bottle back into the radiator top tank. This is the same as a 4 lb pressure cap works, it blocks the overflow above 4 lbs of pressure and as the water cools below 155 it allows a little air into the radiator which prevents the top tank and hoses from being sucked in. This drop below 155 can also happen when driving and I suspect could be your problem when your tank sucks in. The 3 lb pressure cap don't ever open unless the radiator pressure gets OVER 3 lbs. If your engine got hot from low speed driving or long idle time and then driven at highway speeds this cooling cycle described above can happen. G.M.

Re: '35 Large Top Tank Radiator
 

To supplement Dave G's information above, here is a summary of a Ford SK drawing addressing the various radiators used in 1935 production. While suppliers adhered to Ford's performance specifications they used variations of fin and capacity design.

Re: '35 Large Top Tank Radiator
 

Thanks GM. Its something im going to try.

Re: '35 Large Top Tank Radiator
 

Re: '35 Large Top Tank Radiator
 

Thanks for all the great information guys. This Ford Barn is a wealth of knowledge.
GM, I have not put the stop leak stuff or anti freeze in the system yet.
ive been running straight distilled water so far to make sure all the bugs are out of the system.