I'm in the market for a replacement radiator. One that's capable of holding the stat temp, not climbing over. Yes I'm also dealing with potential vacuum leaks and fuel mixture tweaks and I have enough timing in it to blow up any other motor so the typical causes are being counteracted.

Are there quality issues with some of the radiators on the market? They range from $90 for a plastic/aluminum 2-core to $600+ for an aluminum 4 core. Where is the best value? Is a 3-core "good enough"? Some claim a 2-core is good enough. This car has a 350, may end up with a 455 some day. Either way it'll have more power than the stock 4-barrel motor.

Forgot to mention it has A/C too. And I already removed the fan clutch and added a fixed 6-bade fan.

 

A 2 row with a stock 350 4 blade fixed fan no a/c was more than enough back in the day, then a 2 or 3 row HD with shroud 6 blade fan and clutch fan for a/c .
I purchased a 2 row be cool rad and it cools my 76 just fine. I've heard guys that purchased a champion rad for less than half the cost of the be-cool rads and are happy with them
Good luck with your choice.
Eric

 

I'm currently running a 3-core brass "old aftermarket" radiator on my 350 with a condenser, but A/C not set up, with shroud and HD clutch, and all is well.

I bought one of the brass 4-cores on sale from RockAuto last month for just-in-case.

Others have reported good experiences with the 2-row Spectra CU-165 (and similar aftermarket plastic/aluminum "165" units from other suppliers), which makes sense, as similar aluminum radiators work well for similar engines in modern trucks.

- Eric

 

This one has a "heart" by it at Rockauto:
http://www.rockauto.com/en/moreinfo....217427&jsn=393
1 3/4" thick core (3-row?) heavy duty plastic/aluminum for $99. And its one of the few that has the correct 1 5/8" outlet. Do I dare???

 

The applications look right.

Note that this radiator is $360 on eBay.

- Eric

 

Cool! I hope... Plus I have a credit with Rockauto and a 5% code...
Results in a shipped price of $44.95. Worth the risk...
And on Amazon you can get 2- 14" electric fans for $46. $100 solution to overheating (plus a temp switch & relay that I already have).

 

I had the Spectre plastic / aluminum in my 67 when I got it. Once I got the AC working, it would let the motor come up almost 30 degrees, and I had a std. duty fan clutch and shroud.

For my 403, I bought a Champion 3 row all aluminum radiator and after a lot a mucking about, ended up with an HD fan clutch, original shroud, Flowkooler high volume pump and an aftermarket closed system overflow kit. I tried flex fans, electric fans and none of that worked. Not sure if the water wetter had any effect, I put it in when I started the car for the first time, so no way of comparing that one.
Tim

 

Which Spectre did you have? 1 1/4 or 1 3/4" core?

I'm trying things in a scientific manner. One step at a time to see what works. Ditching the clutch fan helped, but not much. Extending the fan closer to the raditor helps, but not much. The water exiting the raditor is still over stat temp of 160, so I'd say that's a clear issue - heat soak in the engine and the radiator is bad. If I can get this cheap radiator to cool with dual fans on a custom shroud, then great. I'll compare the exit temps from what I have now and the new radiator. If it doesn't help, then I look at a richer fuel mixture to cool the cylinders more. I want to install the new FITech system, but have to eliminate a few other bugs first.

 

Remember, water wetter is supposed to be used with straight water (no anti-freeze), so if you use it with anti-freeze, it is not likely to have much of an effect.

- Eric

 

Years ago (long enough that I won't name the brand) I purchased a reproduction radiator. Upon inspecting inside the tanks (inlet, outlet, cap) with a flashlight, I could see that more than half of the tubes were completely blocked with solder. I sent it back and recored my original instead.

 

The last radiator I had recored was an MGB - tiny. Cost $425, and it not only leaked, it was soldered together backward. That's the only shop we have.

 

autocityclassic.com has good aluminum radiators - I recently bought a 2 core drop-in unit with 1-1/8" tubes for my '72 Cutlass - $220 shipped to my door. Had one in my Skylark and it kept me at 180 all day long in FL heat.


Looks like price may have just recently gone up on them but I'd bet they'll have show price specials at whatever swap meets they attend.

 

Well, over the weekend I installed the new aluminum radiator with twin 14" electric cooling fans and the engine temps stayed exactly the same as they did with fixed engine mounted fan. With a 160 degree stat intstalled, the engine likes to run at 190. Next comes a drive with the AFR gauge in place. I may jump right to EFI from FiTech if mixture is the issue. According to recipts, my car has its 3rd replacement carb installed, so I'm guessing that's the next appropriate road to head down... Timing is in the ballpark.

 

Those fans may be junk. What rad did you go with?

 

I had the 1 3/4 core. I would also beware the Ebay electric fans. I bought a kit 'rated at 3600 cfm'. Not likely, as the fans had an 80 watt rating marked right on them. A brand name 1800 cfm is more like 150 watts. I also believe you need a shroud or some other way to ensure air is drawn through the majority of the core. The twin electrics I had covered side to side ok, but left 30% or more on the top and bottom with no airflow while at idle.
If you go back to a mechanical fan, check my other posts about proper depth settings. I got them from a hot rod article and my cooling system is working great.

I'll also give a thumbs up to the FiTech system. It kills the street avenger I took off the engine.

 

The fans I bought have a "blue dot" in the center of the fan motor, a design I've used previously in several other cars with great success. They move more air than the fixed fan that was on the motor, and I have a custom shroud (yes I can fabricate) spaced about an inch off the radiator surface. They cool beautifully, up until about 55 mph. That's what leads me to believe its a lean condition. Freeway air should be enough to cool the motor to stat temps. Period. And its not. I fear the engine build is at fault, but can't pinpoint an issue or component to blame, so I'll go through the checklist until I run out of bolt-on components to replace.
The funny thing is how many people I see posting here that running 195 is ok, when you have a 165 or 180 stat installed. No its not boiling, but you have intense heat somewhere being developed due to a problem - possibly in all cylinders, possibly in just one which would be the most damaging scenario. Fix the problem, or destroy pistons, valves, something expensive. I'll continue to post what I find, as I suspect its not an isolated case.

 

[QUOTE=distributorguy
The funny thing is how many people I see posting here that running 195 is ok, when you have a 165 or 180 stat installed.

I think some guys are just guesstimating when it comes to temps. Oldcutlass, MDchanic and others have mentioned many times . " The need to check temps with a proper gauge". This would eliminate so many other guesses. Sometimes people need to take good advice.
Eric

 

Agreed. My laser temp gauge confirms the radiator is working. Stat is working. Timing is not retarded (quite the opposite to eliminate that heat source.) Today the Innovate LM-1 gets hooked up to verify mixture.
The block is getting heat soaked and I don't know if its poor coolant flow or cylinder heat. Exhaust temps don't indicate issues there, so ??? It may be as simple as needing a better water pump. Dummy lights suck.

 

[QUOTE=distributorguy
The block is getting heat soaked and I don't know if its poor coolant flow or cylinder heat.

You could drop the coolant level down to the top of the trans cooler then run the car until you see the coolant flow.
This is the easiest way to check flow. If poor flow ( dribbling) Remove the rad stand it up, block the rad hose connection and fill the radiator with water from a running hose. When the water starts coming out the filler neck unblock the hose connection. The water should flow out the rad quickly. A good 6-8 inches of flow in a few seconds.
You can also inspect the tubes inside the tanks for blockage or build up with a suspected rad issue.

 

The new radiator is great, so was the old one apparently. My concern now is pump flow. I can see water flow at idle, and quite well, but it could be aerating at higher rpm. I truly suspect the heat is from a lean mixture at cruise. Could be as simple as way too much vac advance. Normally I don't see that issue, but this motor makes 20" of vacuum - possibly more at cruise but it sucks the hose flat that came with the gauge and I haven't replaced it yet.

 

Test run complete.
The fuel mixture is rich across the board. 13:1 at cruise, 12:1 under full load. Spiked to only 15.5:1 on rapid decel. Top of the radiator is at 205 degrees, bottom 160. The radiator is working.
Now for the interesting part. I had a hunch, so I sprayed carb cleaner around the intake manifold. Idle dropped hard and fast when I sprayed around #6. The same happened when I sprayed into the air cleaner. #6 is going lean and getting hot. Looks like I'll be using those fancy aftermarket intake gaskets after all. I'll double check the plug color on #4/6/8 to see what's happening, but I think I found the smoking gun. Temps are 10-20 degrees higher there as well, at both manifolds. Bingo. Yahtzee. Bob's your uncle.

 

Excellent detective work! Good one to remember.

 

A vacuum leak will do it. What gaskets are in there? The Olds 260, 307 and 350 are usually easy to cool, a 403 or 455, not so much. My current rad in the 88 CSC only ran warm due to too much stop leak in the rad, that one will cool the 260 just fine. I have been running a CLR(acid) mix in the 70 to clean it out.

 

I don't know what's in this engine. I suspect its a stock metal valley pan setup. Plus it was supposedly rebuilt, so the intake likely never got shaved with the heads.

I use a mixture of 6:1 water to muriatic acid to clean out the radiator (maybe not that strong - its more of a guess). The old one was pretty clean when I changed it out. Shooting from the hip at this point. Hopefully I'll have time to fix it Fri/Sat. The schedule is stacked pretty tight this week.

 

Interesting afternoon of discovery...
I just pulled the intake.

Good news: the inside of the block is immaculate, like it was recently rebuilt, verifying the 5k miles that's roughly been put on the motor since the receipt said it was rebuilt.
The intake gaskets were thin steel, so they likely never sealed between the original manifold and the machined heads/block.

Bad news: the intake had just been removed from a filthy high mileage motor and dropped onto this block, without so much as cleaning it. The inside is stacked with carbon build up. Filthiest I've seen short of pulling apart a really old core motor.

 

So what rad did you end up purchasing? Or rad fan combo?

 

The one on post #4.
Cheap Ebay fans that I've used a bunch of - twin 14" and I made a custom aluminum shroud.

 

I hope you can get enough air flow through, the shroud looks really close to the core.

 

Looks are deceiving. Not my first rodeo. Its a tried and true design, distanced 3/4". As you may notice, if you actually read my posts, its cooling great - its dropping coolant temps from 205 to 160. I don't think you can ask a radiator to shed much more heat than that. I just need to get initial coolant temps below that 205. Freeway speeds are my issue. Always were. At idle it'll hold stat temp indefinitely. I just glued the intake in place with good gaskets and sealant, not a Fel-Pro shim-type gasket set on milled heads and block. Turns out the intake had never been cleaned when the engine was rebuilt, so the intake gaskets leaked the whole time - not under my watch. I just hope that's the only issue. Its running rich as a pig, so I'll adjust the float and note jets while its apart.

 

Are all the factory air dams in nplace? What pulleys are on there? I had a Mr Gasket high flow thermostat slowly go bad, fine around town, would completely close up or close to it at speed. I would feel flow when I got back at idle.

 

Quick update after the new intake manifold gaskets. I wanted all the sealant to set, so I left it alone for a few days. No leaks now. It runs better, the exhaust even drones less, which was unexpected. Timing is now over advanced and I can hear pinging, so that will get addressed immediately. The car engine ran a little cooler, never getting over 185 (160 stat). That's an improvement, but not what I'm looking for. I guess the next step is a good water pump. The best I could find is the one with a billet impeller. $120? If that's what it takes, it seems the next logical step.

What surprises me is how hot the heater blows. Is this hot running issue a water pump problem, or is there an issue with coolant not circulating through the block very well???Would an additional hose from the back of the block to the water pump help move more hot coolant to the radiator? Is the issue the impeller or the passages the coolant travels through? Or am I missing something else??? Cam timing???

 

We would all like to know.


Doubtful.


All good questions.


I have owned at least 2 older V8 cars with this problem (that I can remember), a '68 Olds 88 with w HC 455, and a '68 F_rd Galaxie with a 9:1 390.
In both cases I replaced the radiators and water pumps, set the timing, changed the thermostats, flushed the blocks, used WaterWetter, and did all of the common sense things, and in the end, was only able to solve the problem the old fashioned way: By selling the car.

Because of this, I am carefully following your experience here, since you are systematically replacing parts and retesting, which allows me to learn without getting frustrated or spending money.

The only thing I can say is that since those two experiences with engines that I could not keep cool (the F_rd had a temp. gauge and heated up on uphihills on the highway in warm weather and the Olds switched on its HOT light when I used the A/C on the highway for more than 5 minutes, less when in traffic), I have made an effort to aggressively attack rust inside the block when I had the engine accessible, and I have not had more problems - whether that is the reason I haven't had problems, I do not know.

Keep it up, because when you finally fix this, it will help all of us, sooner or later.

- Eric

 

Well, there must either be a cause, or multiple small causes. These cars didn't overheat like this when new. My temps stay stable whether the A/C is on or not, which tells me the radiator is working as well as it can. It only happens at cruise (well over 55), and since the mixture is WAY too rich, it must be either retarded cam timing or water not flowing through some areas of the block. If a water pump doesn't fix it, the engine comes out this winter.

I may have to set up a GoPro to watch the lower radiator hose...???

 

I am just experiencing a severe cooling issue in my Dakota. In this case, I am sure it is a cracked head must be leaking into the coolant passage and over heating the motor. Two different thermostat's, one is a Motorad that is design to lock in the open position when it over heats and it worked. I also tried no thermostat, same thing. I am replacing both heads and getting the aluminum intake pan from Hughes, fix a couple of known issues and gain power to boot. I think this explains my come and go miss. I still haven't blown a head gasket, I think the 7 psi rad cap I am running vs the stock 18 psi cap saved them. My 88 Cutlass has always ran on the warm side, first rad that came with it was junk. Also should have never bought the severe under drive pulleys and Mr Gasket Thermostat no flow, I mean high flow thermostat. You know how long I chased that one. It would flow at idle speeds and around town, on the highway, would basically close up. So you could feel the flow in the top hose! I have all the air dams in place, even fixed the ripped one under rad with part of a chrome fan shroud. The Champion 3 core that was marginal in G body cooled great, ran at lower temps with a 195 thermostat in the Olds powered 4x4 then with a 160 thermostat in the G body. Having an A body, you can go with a much larger rad than a G body which should help. I am hoping my 2 core is enough for my 350 in the A body. I have sort of plugged up the rad in the G body with stop leak. It will be fine for the 260, but no good for my planned 424 stroker and 1/8 mile drag car plans down the road, the F body Griffin dual 1.25" core rad will be the only to cool that thin wall beast.

 

FlowKooler pump ordered. $119 at Summit, free shipping and handling.

 

I am running that pump, made no difference for me. It is lighter and mine has to be 10 years old. It is a closed vs an open impeller but they slapped a plate on an open impeller to make it one.

 

The new ones appear to be a CNC machined aluminum impeller, anodized.

 

I sent one of those back and am currently using a parts store reman with a stamped steel impeller. No issues with cooling in our summer temps.

If that water pump solves your problem I will be surprised.

 

The thermostat has zero effect on the running temperature of the engine. Operating temperature is totally dependent on your cooling system. A thermostat is there to block the coolant flow to get the engine UP to operating temperature. This is most important in cold weather, to help it run smooth, minimize stalling and minimize developing harmful deposits. Most of our engines were designed to run at around 200 degrees. Running too cool can cause engine deposits and inability of the oil to burn off moisture with can create acid in the oil...not a good thing.

Once a thermostat opens, it is open, whether it's a 160, 180 or 195, and the coolant flows. A 160 has the same opening size as a 195, so flow is the same. If your cooling system is inefficient, the temperature will rise to the point that it can maintain temperature. Of course, using the A/C, driving fast or going up a mountain may also cause the temperature to rise unless the cooling system is efficient enough to compensate.

 

Brown, that's why I'm systematically trying to make the engine capable of cooling to 160. If I can do that, then I can comfortably get it to run at 180 and know I have room to spare, so to speak.

Fun, why did you return the pump???