I recently installed an AC/Delco "350" '92 Z28 radiator in my '92 RS with a new 350. The part numbers between the 305 & 350 are different, but the size, shape, fittings, and everything else look identical to my old 305 radiator.

Is there really a difference? I needed a new radiator anyway, but I'd like to think that the "350" radiator was designed for the power/heat of a 350, right?

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'92 RS, ZZ4 10:1 350, Edelbrock 6085 heads, Crane 208/214 467/482 cam, GM/LT4 1.6 true roller rockers, Holley Projection TBI intake, Holley 670 TBI, SLP/Jet-Hot 1-5/8" headers, Catco 3" cat, Flowmaster 3" catback, Hughes 2500 stall converter, stock 700R4, Auburn Pro posi w/3.42, 17x9" SS rims w/BFG tires, Medium Quasar Blue w/white SS stripes, 48,000 miles....

 

I just bought a radiator on Saturday for my 88 IROC with the 5.7TPI. In the 1988, the difference doesn't necessarily come down to the engine size but rather the options.

If your car was purchased with the Oil Cooler Option, the radiator needs the hose hookups for this. The 5.7 required this oil cooler and therefore required this "other radiator". If a 5.0 was ordered with the oil cooler, it would also require this radiator rather than the "standard" one.

I am pretty sure that this is accurate, based on my research.

 

I have a stock 305 5 spd. I want to put in a 350 in a year or so, but, I need to replace the radiator now. Can I get one with the oil cooler, and not hook anything up to the oil cooler, right now?? Id hate to get a new rad, only to have to replace it next year.

 

Well, you don't need to put the oil cooler in. It is just a thing that is sandwiched between the block and the oil filter that circulates coolant through it. You could put it on your 305. If you want to put it on the 350, but want a new radiator now, then just get a rubber bypass cap from an auto parts store to seal the fitting on the radiator until you need to use it.

89 Transam GTA, a few bolt ons

 

Scott...I replaced the radiator in my 90 IROC with the 5.7 option. With one from my 91 rs with the 305. To me they looked identicule also,the core width was the same i didnt check the tube size inside though. They may have wider tubes for the 350. Just guessing i think they are the same.

As far as the radiator with oilcooler is concerned, they are the same.. at least on my 90 they are. The one from the 91 rs has the same water outlet. Its in the same postion with or without the oil cooler. GM just bypassed the hose going into the heater core and ran it down to the oilcooler and back up to the heater core. If you didnt have the oil cooler you would just run it straight to the heater core fitting.



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Black 90 IROC, L98, A4, 323 gear. SuperRamed 406 in the works!

 

OIL goes through the oil cooler lines....not antifreeze. it gets pumped into a separarte little sealed "radiator" inside the plastic cap on the side of your existing radiator. this separate "radiator" is cooled by the antifreeze flowing through your existing radiator. the oil gets circulated from a bypass after the oil pump in the motor. it bolts right on where the oil filter would go, then the oil filter is screwed into the adapter. instead of going straight from the pump to the filter, oil goes from the pump, to the cooler, then the filter. this is the same thing as your trans cooler...there's trans fluid in those lines...not antifreeze. so if you have a radiator w/ the oil cooler, just leave the caps over the oil inlet/outlet holes until you're ready to use them.

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350, Comp 262, Edelbrock Performer intake 600 cfm carb and exhaust, headers

 

CamaroZ_85...There is antifreeze in the lines not oil. The factory system isnt designed like that. Aleast not on my 90, the cooler is sandwiched between the oil filter and block. All it does is circulate water from the radiator fitting that we are talking about. Down to the cooler sandwiched between the block and filter. Back up to the heater core. Maybe Not the best design but thats how it works.

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Black 90 IROC, L98, A4, 323 gear. SuperRamed 406 in the works!

 

Oil goes through the lines on my 91 not coolant.

 

evilho7810...If you have the factory oil cooler and you have oil in it. You have a problem...Ive had mine apart and i can tell you it has coolant circulating thru it not oil.

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Black 90 IROC, L98, A4, 323 gear. SuperRamed 406 in the works!

 

There is an oil cooler in the stock radiator... it cools transmission fluid.
The stock (on the cars that had them) engine oil cooler is a sandwich adapter plate above the oil filter. There are 2 lines running from it that are filled with coolant, not oil. There was never a stock engine oil cooler on a 3rd gen F-bod that had oil passing through the lines.

 

Madmax...

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Black 90 IROC, L98, A4, 323 gear. SuperRamed 406 in the works!

 

Scott, I would like to get a definitive answer too.
I had heard that there were two different radiators, one was a 1 row and the other was a 2 row. I went to a local shop and We looked up replacement radiators for various f body cars, 305 and 350 and all were 1 row and Identical dimensions.So, other than an oil cooler I was under the impression they were all the same. I am still wondering though if this is correct because I saw a post on this site about a 3 row radiator from autozone or something. I would like to know for sure.
I am definitly going to add dual fans to mine
before next summer hits and if there is a better cooling radiator I would like to ad that too...........bob


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91 camaro RS L03 convert,
t-5, ultimate TBI mods,TBI spacer,SLP 1 5/8 headers,
3"cat back, 3.42 torsen posi,alston SFC's,Global West LCA relocation brackets

 

First, coolant runs through this line, not oil (at least on my system).

Second, coolant is also run to the transmission with this same unit.

Third, I have to believe that the extra features can be "capped" at the radiator in anticipation of a future engine swap with no problem. I personally would do this since the cost isn't all that much.

Try going to www.radiatorinfo.com and browse the "Online Catalog" for your year of car. Note that with different engines, you can still "substitute" one for the other. Also note that many of the radiators also are accompanied by pictures.

 

Sounds like there is a great deal of confusion about coolers here... An oil cooler is a device used to cool oil temperature, weather it be motor oil or dex3/power steering fluid. Coolers have BOTH fluids; antifreeze/water and oils running through them in SEPERATE chambers. This is how the oil is cooled. I am a boat technician by trade, trust me I know plenty about coolers, as many high performance motors in marine applications involve coolers. The oil cooler in any motor will have oil AND coolant lines running to it.

 

Ok, the coolers thing is getting out of hand!

1. Oil cooler. GM's factory oil cooler has oil flowing through the center of the part on the block, and coolant on the outside, along with coolant running through the lines going to it. I believe the reasoning for this is so that the engine doesn't hold more oil, but slightly more coolant. It would also be a pain to get the oil out of the cooler lines every oil change.

2. Transmission Cooler. This cooler is basically a tank inside the radiator. Transmission fluid flows through it. This design has been used for a very long time.

I'm not a fan of either setup, because there is the potential of getting the coolant mixed with the oil/fluid. That is why I like the next one.

3 External Coolers. Many thirdgens have a power steering cooler. It's usually just a simple piece of steel tubing that runs below the core support. Aftermarket transmission and oil coolers are generally like this. They rely on airflow to cool the oil/fluid.

Now to the point of the topic, I believe that the radiators are the same for the reasons already mentioned. I'm also pretty sure the 305 radiator would be fine with a mild 350. GM thinks so, too. Just look at the parts list for the conversion kit for the 82-86 305 f-body's to the 350 H.O.



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Working on:
'84 Z28 LG4 305
Added dual elec fans.
145 MPH IROC Speedo
Building 430 HP 350
using primarily GMPP parts.
Block is in shop!

Awaiting results from all 8 ASE tests.

Starting to look like the Kicker poster child!

 

my car has a factory oil cooler, i thought that this option was only available with the 350. was it? because my motor is stock, and it definitely has one.

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87 IROC-z 305 TPI 5spd Borg warner 9-bolt 3.45 posi 4 wheel disc,8.8 Accel wires , bosch platinum +4 plugs,gutted air box,k&n oil filter,synthetic oil 10w30

 

I'll go out and check for sure, but I think my 1984 stock radiator for my 305 has a separate radiator located in front for tranny fluid only. There is a second 1 row radiator behind that that the coolent runs through. I also think there are ports that are plugged off for some smaller hoses, but coolent flows out those too.

I don't think I have any lines that run to either radiator that has engine oil (10w-30) running through it...

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1984 z28 w/ a 357 cu in. monster engine which is looking like the posterchild for Edelbrock... all the suspension stuff... 9-bolt posi disk is in... K&N filter... 93 octane...

-=ICON Motorsports=-