951 Radiator and Cooling Modification

[Harry_Moore]

Life is funny and amazing at the same time.

While driving during one of the rare rain storms in Southern California I hydroplaned on the freeway and slammed into the concrete center divide - no other vehicles were involved!!! I walked away without a bruise or a scratch…but my daily driver Ford Focus was totaled. BTW, the red is the stitching used on the airbags, not blood.
This means I have to get the jag running - oddly enough I was on my way to the office when the accident happened. Not only was it the first time back in 2023 but it would have been my first time back in almost two years!

I charged the battery in the Jag and started it up. And that is when the coolant poured out the lower passengers side of the radiator. Since this was an original 4 four, core brass, custom made radiator, I decided to try out the one core aluminum radiator with plastic sides that is commonly found on 1987 - 1990 Camaro’s. Here is a link to Andrew’s page from Jaguar Specialties about the radiator: Jaguar Specialties

Also, here is a link to the radiators on Rock Auto.

Here is the old leaky radiator after I removed the fan and the fan shroud:

Here is the new single core aluminum radiator next to the original 4 core radiator. They are the same size and shape, however the upper radiator hose fitting is 1 1/4 inches and my old one was 1 1/2 inches so I have to find the correct hose that has both these dimensions.

I did have to clean up the hose connections on the plastic radiator because they had left over molding pieces that were very sharp. So I took a small file and smoothed everything out:

This “951” model radiator has a heater hose connection on the passenger side. It would be nice if there was a version that has one on the drivers side because it would be a straight shot to the heater core. After I get everything up and running I might use this connection on the radiator and route my heater hose around the back of the engine instead of over the manifold, but first things first.

I was disappointed after making the modification to the radiator header plate so I could access the stock radiator cap (I used an in-line radiator cap on my upper radiator hose - see the first image) because once I cut the opening and put the radiator in I CAN NOT REMOVE THE RADIATOR CAP.

There is not enough room for the cap to come up. The radiator is centered on the front frame and I am using the stock rubber GM supports.

So, I might go back to the in-line radiator cap, but need a fitting that is 1 1/4 inch on one side and 1 1/2 inch on the other side. Here is an example from Moroso part number 63740: Moroso RADIATOR HOSE FILLER

I will keep tweaking things this week. Hopefully I can get everything sorted out by the weekend.

[davidsxj6 (David)]

Bad spot to cut a hole. Weld a box over it, maybe a bit of thin walled pipe or so, this brace takes a lot of load.

[rtloft (Bob Loftus)]

I used a new 1996 Corvette radiator, part number 2228. It has an aluminum core with plastic tanks, no filler neck and one internal cooler on the right side that I am using for the transmission fluid in addition to the external cooler. It fit perfectly in the XJ6 with the use of GM rubber saddle mounts. I used this model because I did not want to have the filler neck and cap as part of the radiator. I have a GM coolant header tank in my system that includes the cap. The 2228 is about two and a half inches narrower than the 951. Have had no issues with cooling driving in Phoenix.
The hose connections on the 2228: Left Inlet Connector Size: 1 7/16’‘, Right Outlet Connector Size: 1 11/16’‘.
The hose connections on the 915: Left Inlet Connector Size: 1 5/16’‘, Right Outlet Connector Size: 1 9/16’'.

[rtloft (Bob Loftus)]

My only reason for posting this was to inform that there is an alternative to the 951 radiator for poeple who don’t want the cap on the rad and don’t want to cut up their upper radiator support beam. I’m not casting any shade on anyone who has used or advocates the 951 solution. Just saying there’s not just one right answer.

[Harry_Moore]

Hi Bob,
@rtloft

Thank you for this information. This is fantastic. Since I have not filled the radiator with fluid yet, I am going to try and exchange it for the one you mentioned.

By chance do you, or anyone, know of this style radiator (no cap, cooler on the passenger side) but with the heater hose connection on the drivers side instead of the passengers side? If the heater hose was on the driver side I believe it would make for a cleaner installation of the hoses.

Here is a screen shot of the 2228 style radiator with a red circle showing the location of the heater hose connection. I have searched the photos at RockAuto looking for the heater hose on the driver side but have not found one yet.

I wish there was a website/app where I can enter in the characteristics of a radiator and it would show me results. This way I can find the correct size and configuration of the radiator without spending hours looking at pictures!!! If anyone knows of an app like this please let me know@

[Benzme (Don)]

My solution to all of the above was to use the original radiator tanks with a new non-Chinese copper core. Worked a treat. The replacement plastic tanked alloy core rads are mostly Chinese rubbish.

Edit; the cost was ultimately a lot less, both in grief and dollar wise.

[rtloft (Bob Loftus)]

Harry,
The small hose barb on the upper right side is not intended to be a heater hose connection. It’s only 3/8" dia. Its purpose is to connect the upper most location of the radiator to a separate coolant reservoir tank (where equipped. The mid 90’s Corvette had one). It allows excess air to vent from the radiator to the reservoir tank. If you don’t have a separate reservoir coolant tank in your system, cap off this barb connection with a rubber cap and secure it with a hose clamp.
From your pictures it looks like your engine is carbureted. If this is the case you should be able to connect your two heater hoses in a more conventional manner. The hot water supply hose connected to a 5/8” barb fitting protruding from the forward right corner of the intake manifold. The hot water return connection to a 5/8” or ¾” barb fitting on the water pump. Your system should have the ability to be configured this way but may have threaded plugs in one or both locations. You would need to replace the plugs with barb fittings which are available at any auto parts store. Some OEM Chevy V8 installations did send the heater return to a separate connection on the radiator. Either way will work fine.