1969 bb aluminum radiator

[Paul B.]

hello,

i'm looking at a 1969 L68 manual "survivor", that has an aluminum radiator and expansion tank. the literature i have, indicates that L68's came from the factory with copper radiators and aluminum expansion tanks.

am i looking at a car with non-numbers matching radiator?

the car would be a lot of money for me and i need to know as much as i can about what i'm buying.

paul b

[Duke W.]

Re: 1969 bb aluminum radiator

The only big blocks of that era to have aluminum radiators were '65 L-78 and all L-88s, and the BB aluminum radiator was wider than the ...316 radiator used on SBs. All others had brass radiators as OE. Since all brass radiators had integral tanks they were never equipped with remote aluminum expansion tanks. Only Corvettes originally equipped with aluminum radiators had the remote aluminum expansion tank since the design of the aluminum radiator did not include integral tanks.

I would be suspicious that this car was originally a SB. There are other ID signs. All BBs had 9/16" rear anti-roll bars (no '69 SB was equipped with a rear bar), the BB front anti-roll bar should measure 7/8" versus 3/4" on a SB. The axle should have cap type side yokes. Also, the BB fuel pipe terminus is a couple of inches further forward to be in the proper location for the BB fuel pump inlet nipple.

The tach redline could also be a clue, although it's tricky because the L-68 redline varied over the years, and I'm not sure what the '69 L-36/68 redline should be, but someone knows.

Duke

[Dick W.]

Re: 1969 bb aluminum radiator

The ONLY 1969 BB with aluminum radiator was the L/88. I would look for other obvious items such as a rear sway bar, tachometer, whether the rear half shafts have U straps or steel caps, and closely scrutinize the engine pad.

[Jeff G.]

Re: 1969 bb aluminum radiator

The only cars in 69 that had an aluminum radiator was the L88 manual, 350/300 manual, 350/350 manual cars. Otherwise, all other 69 vettes had a copper radiator. If it's a true original aluminum radiator it would have a label on top drivers side saying "Harrison". Also on the top of the radiator should be a foam insert that is pressing up to the fan shroud. I have a very original L36 manual with AC and can take pics for you.

[Joe L.]

Re: 1969 bb aluminum radiator

Since all brass radiators had integral tanks they were never equipped with remote aluminum expansion tanks. Only Corvettes originally equipped with aluminum radiators had the remote aluminum expansion tank since the design of the aluminum radiator did not include integral tanks.

Duke

Duke-----


1969-72 big blocks equipped with copper/brass radiator were also equipped with external supply tanks. For non C-60 cars, the supply tank was the same aluminum unit used for 68-72 small blocks with aluminum radiator and 68-71 big blocks with aluminum radiator (i.e. L-88, ZL-1, and LS-6). For 69-72 big blocks with C-60, a "cylindrical" brass external supply tank was used.

It is true that the 69-72 copper/brass big block radiators did have integral tanks. But, for whatever reason, they also used an external supply tank.

[Joe L.]

Re: 1969 bb aluminum radiator

hello,

i'm looking at a 1969 L68 manual "survivor", that has an aluminum radiator and expansion tank. the literature i have, indicates that L68's came from the factory with copper radiators and aluminum expansion tanks.

am i looking at a car with non-numbers matching radiator?

the car would be a lot of money for me and i need to know as much as i can about what i'm buying.

paul b

Paul-----


What is the configuration of the aluminum radiator? Is it an original "stacked plate" design or a later style? Original aluminum radiators and all GM replacements for same had a date stamped on the top of the radiator. It will be seen as 2 digits (for the year) and a following alpha character (for the month) and will look like "69G". Does the car's radiator have this and what is the coding?

What is the width of the radiator core? It will be either 19" or 21" if it's an original aluminum radiator. Actually, if it's an original radiator or original GM replacement for same, you don't even really need to measure the core width to determine what type it is. Just look at the upper radiator hose inlet.

For the small block GM #3155316 radiator the tube will be short and STRAIGHT. For the L-88/ZL-1 big block aluminum radiator, GM #3007436, the tube will be longer and CURVED.

[Paul B.]

Re: 1969 bb aluminum radiator

thanks for your help,

the radiator has a coded harrison label and i believe it to be oem aluminum. judging by your replies, somethings not original, either the aluminum radiatior or the L68. the asking price seems low for an L68 convertible. but what if it's not a real L68? i will have to investigte further.

thanks again for the insight

[Duke W.]

Re: 1969 bb aluminum radiator

Duke-----


1969-72 big blocks equipped with copper/brass radiator were also equipped with external supply tanks. For non C-60 cars, the supply tank was the same aluminum unit used for 68-72 small blocks with aluminum radiator and 68-71 big blocks with aluminum radiator (i.e. L-88, ZL-1, and LS-6). For 69-72 big blocks with C-60, a "cylindrical" brass external supply tank was used.

It is true that the 69-72 copper/brass big block radiators did have integral tanks. But, for whatever reason, they also used an external supply tank.

Well, that's a new one to me. I assume that the these brass radiator configurations with a separate expansion tank had no cap on the radiator tanks?

I expect the external expansion tank (and cap assuming they have one) had something to do with the angle of the radiator that didn't allow the top of it to be high enough to allow ease of filling, and the fill cap on the expansion tank is higher than the top of the radiator as it is on models with aluminum radiators.

Duke

[Joe L.]

Re: 1969 bb aluminum radiator

Well, that's a new one to me. I assume that the these brass radiator configurations with a separate expansion tank had no cap on the radiator tanks?

I expect the external expansion tank (and cap assuming they have one) had something to do with the angle of the radiator that didn't allow the top of it to be high enough to allow ease of filling, and the fill cap on the expansion tank is higher than the top of the radiator as it is on models with aluminum radiators.

Duke

Duke----


Yes, the 69-72 big block copper brass radiator has no integral filler; the only way to fill the system is through the external supply tank.

The 1968 big block copper brass radiator did use an integral filler and no external supply tank. Also, the 1973-74 big block used a radiator which was virtually identical to the 69-72 except it had an integral filler and used no external supply tank (although 73-74 did use a coolant recovery system and reservoir). 1973-74 small blocks used the same radiator as big blocks.

[Michael B.]

Re: 1969 bb aluminum radiator

Although the radiator is a DeWitt's aluminum replacement painted black the radiator and shroud is the correct original configuration. The upper hose is also incorrect for the 1969 L68.

[Jeff G.]

Re: 1969 bb aluminum radiator

Michael, Looks like much resto work has been done. The lower than norm price you mentioned does perplex the purchase question. I hope you do your research with numbers. Assuming the pad lines up, I'm curious about the block castings, carb numbers & dates, trans VIN, etc. I doubt that the altenator, AIR pump, and MC are original.

Here's another L68 I've looked that's restored that's very nice but I don't think is quite worth the asking price.

http://buyavette.net/c100.html

[Joe L.]

Re: 1969 bb aluminum radiator

Although the radiator is a DeWitt's aluminum replacement painted black the radiator and shroud is the correct original configuration. The upper hose is also incorrect for the 1969 L68.

Michael-----


The AIR pump is also incorrect for a 1969 L-68 or L-71.

Using the DeWitts "direct fit" aluminum "reproduction" of the original copper brass is a GREAT move. Near original configuration and much improved cooling capacity. In fact, this radiator has significantly higher cooling capacity than ANY radiator EVER originally installed in ANY 1953-2009 Corvette.

[Michael B.]

Re: 1969 bb aluminum radiator

Don't be backing up on me Joe. We have talked about that AIR pump and the relief valve. It's an Oct 04 1968 build date and you agreed that some of the left over 68 pumps were used in early production 69s.

I'm getting ready for both Tahoe and San Jose. Do you think I should change it?

I have to say that this radiator has been great. I have participated in several 4th of July parades here in Sacramento without exceeding 200 on the gauge.

[Joe L.]

Re: 1969 bb aluminum radiator

Don't be backing up on me Joe. We have talked about that AIR pump and the relief valve. It's an Oct 04 1968 build date and you agreed that some of the left over 68 pumps were used in early production 69s.

I'm getting ready for both Tahoe and San Jose. Do you think I should change it?

I have to say that this radiator has been great. I have participated in several 4th of July parades here in Sacramento without exceeding 200 on the gauge.

Michael-----

I don't think I ever said that some 68 pumps were used on early 69's. I may have said it's possible they were used because I do consider it a possibility. However, I certainly have no definitive information that they were used. I do not know how this would be handled in judging. Actually, there's a date code stamped on the pump and that may be part of the judging "equation".

The 68 style pump was definitely used for 1969 L-88's and ZL-1's which also used the 68 diverter valve.

A 1969 diverter valve can be used with a 68 style pump (as is the case with yours). However, a 69 style pump should not be used with a 68 diverter valve.

[Michael B.]

Re: 1969 bb aluminum radiator

Joe,

I didn't realize how many times you have answered the 68 vs 69 & later AIR pump question. Seems to be a lot of 69 and later cars out there with pumps with relief valves on them. How they got there is anyone's guess.

For what it's worth, the 68-69 JG does say "In 1968 and early 1969, the pressure relief valve is mounted on the case; in later 1969 it is not."