Overheating Issues, Perplexed
 

Newly rebuilt 427 side oiler in a Hurricane. As I have been working through putting a few miles on the car and tuning it I continue to suffer an overheating issue that I can't solve. It runs nice and cool down the highway at 80-85C, but it jumps up to 100-110C at idle. I was at a local car show last weekend and it was suggested I needed a fan shroud to help out at idle. I ordered an aluminum shroud from JEGS and I also purchased a Zirgo 3650 cfm fan in lieu of the 2300 cfm that came from Hurricane. Trimmed up the shroud and installed it and the new fan yesterday, expecting a big improvement. Nope, worse. Headed out about 6PM last night (outside temp was about 90*)and she hit 100C at 50 mph before I got a mile outside the subdivision. I could keep it between 100-110C going down the road (ambient temps were 90and humidity was high) but I was pretty nervous when I finally parked it. The shroud killed the airflow at road speed and didn't help squat at idle. But the fan is clearly moving a tremendous amount of air, I can feel it at the back of the car on the garage floor when its running.

From a cold start it takes the car 7-8 minutes to get up to 85C. Beyond that, idling in the driveway, it will slowly climb to 100C, possibly beyond. I can cool the radiator with the garden hose and drop it back to ~90*C for a couple minutes, then it starts to slowly climb again. With the cap off I can see when the t-stat opens and coolant starts flowing.

Also, I bought this car turn-key minus from a guy that had put 1500 miles on it from new with an all-aluminum 482 KC Pond engine. He says he had zero cooling issues. I am running that same radiator and even using his hoses.

So:

- New engine with 250 miles that ran cool on the dyno and runs 80-85*C down the highway (without that shroud)
- Good oil pressure, 55-60 at road speed, 25-30 at idle. After 15 minutes of warm-up oil temps parallel engine temps, max out around 110C.
- New Ebrock water pump on the engine when built, bypass hose installed.
- Expansion tank was vatted, leaks repaired and pressure tested to 20 lbs.
- 180* hi-flow t-stat from Cobra Valley and a 180* electric fan temp switch from BeCool. Its on a 30 amp relay but I have since wired it direct and its starts with the car.
- 70/30 distilled/Dexcool with a bottle of water wetter.
- New Stant 16 lb radiator cap.
- Timing and carb mixture close enough that it seriously doubt it could be causing this.

Ideas? Thanks in advance.

Just some elementry things to consider: What are the pulley sizes, are you possibly underdriving the waterpump? What is the total ignition timing that you are running? Does the lower hose have an internal spring to prevent it from collapsing when it gets up in the RPM range? Lastly, any possibility of partial clogging of the radiator, and is the radiator LARGE enough?? Is the gauge accurate?

One of a few things could be the , too small a radiator vs what it needs to cool (what works for a small block does not always work for a big block). Timing too far advanced. Water pump or it's pulley not turning fater enough to move sufficient coolant (what are you using for coolant and in what mixture) through the block and radiator. Finally (for right now) not enough air being moved through the radiator.



Bill S.

I've had a similar problem. To much engine in too small a space. Two of the suggestions I got were: raise the back of the hood when running using a block of some sort and or install two blowers (boat type) to exhaust the air out the bottom. Both will help considerably
John

I have tweaked the timing between 16* and 20* base and 18* additional, coming in at 1200 and all in by 3000. Hasn't really seemed to matter, no pinging/knocking/dieseling on accel or shutoff. Carb is a 750 Mighty Demon annular/mechanical, that just replaced a 850 Speed Demon that ran great on the dyno but like sh^! on the street. Mixture is around 2 turns out on the screws, I have chassis dyno time scheduled to do final tuning as soon as I can sort this out. Plugs are tannish brown and look good. Car does need some final tuning but it hauls some serious a$$ for only 450 HP 485 ft lbs tq.

Water pump pulley is 6.5" diameter stock and balancer pulley is 6.5" Professional Products SFI. Bill, coolant mixture noted above in original post. I started at 50/50 distilled to Dexcool but I am down to 70 water 30 Dexcool +1 bottle WW. Hasn't made a difference. Radiator size is where I think this is headed.

Guage is accurate, this damn thing is getting hot according to an IR gun. Hoses have springs in all lower bends.

I am running the expansion tank at half full per threads here. Should I top it completely off and see if that other quart makes any difference?

More coolant, less water, a full bottle of water wetter/motor max/royal purple , top it all the way off.


Also, again keep in mind when you are not moving there is no real airflow going through the radiator (the fan does not pull enough through it, really) to create enough evaporative properties to sufficiently cool your BB. I'd question the size of the radiator and the volume of the water pump you have installed.


Bill S.

PS: Last week I had ERA188 out on RT76 in Philly, stop and go traffic, 89 degrees, the oil temp never rose past 180 degrees, the water temperature would sometimes go up to 210.......Another friend had his car top 240 degrees in the same traffic, differences in car (I have a 427BB he has a 427sb stroker) are really the radiator and the water pump capacity......Ambient air temps were the same, humidity the same, not the same time in stop and go traffic, but still the same type of stop and go traffic.......

PSS: Try backing off five car lengths from the vehicles in front of you and allow crisp clean flowing air to make it through your radiator and engine compartment..................

So I was at 50/50, you are saying increase the coolant above 50%? Has anyone heard of new Edelbrocks underperforming? I guess I can remove it and disassemble it and take a look at the impeller.

Even in my other cars I never get closer to the vehicle in front of me than 4-5 car lengths.

With your geographic location, 100% coolant, and your choice of "enhancer", water pump is indeed suspect as is the size of your radiator (which you have not posted, or posted a picture of).......


Bill S.

No such thing as "too much motor in too small a space".

Stupid stuff first:
T-stat.I've run into bad T-stat after bad t-stat.Six in all.Either failed out-right or in-accurate opening temps.
I'd install a restrictor instead of a T-stat JUST for the trouble shooting process.
Collapsing lower hose-as mentioned.
Correct pulley size-as mentioned
Correct spacing between back of the impeller and the back of the water pump.Too much space and cavitation results.
If it's a parts store pump,double check the impeller to make sure it spins the "right" way.
Radiator must be aluminum of sufficient size.It also must be sealed to the nose so that every "drop" of air entering the nose is forced thru the radiator.

All things being equal,a shroud + fans with enough CFM should in no-way make things worse.
My SPF with a Side-oiler NEVER overheats in Tucson.The radiator is Aluminum one from a V-12 BMW and has twin fans that are shrouded.Standard SPF stuff.

The above is written on the premise that jetting/timing and all other motor functions are with-in parameters.

I just saw this in your post: Dexcool?!!!!Get rid of that SH!T NOW!!!!Deathcool is one of GM's biggest blunders.It eats gaskets and other things.

I have tried three leading up to the hi-flow and it has made no difference

The restrictor works just like a closed thermostat. The car is fine until the temps open the thermostat and then they just keep climbing. Restrictor will tell me nothing at that point.

Covered above.

Its spinning the right way, but it could be failing or cavitating.

Others runnning this radiator have made it work but as we know, each car is different. Given that we've ruled out the engine (for the most part) its got to be an inability to dicharge the heat in the radiator, either due to flow/restriction/water pump issue or insufficient radiator/cooling system capacity.

Thanks for the advice though, but I am sure its not my problem as of right now. I had 10 gallons of it left over and decided to use it through this process of puking/discharging and running out on the ground from t-stat changes. I will be running Shell ELC once this is resolved, but I am sure someone will complain about it too.

Well you are the first guy who has suggested 100% coolant. The radiator is a 2-row 27"X19" with a 22.5" wide x 17.5" high cooling surface. Here's a pic:

http://www.hurricane-motorsports.com.../radlarge1.jpg

I have no idea where Hurricane sourced it, build sheet doesn't give a part #. It does not compare to the SPF or ERA radiators I have seen, the sides are only 3" thick and the finned area is a bit thinner, maybe 2.5-2.75.

X2 on the Dexcool. turns to brown sludge and blocks radiator passages. eats gaskets. Google Dexcool and sit back and read the stories

Elmariachi, it is either flow or radiator, but you're right, from what you've said, I'm betting it is a radiator issue. If the size is/was okay, I'd bet it's plugged with crud. Use an infrared temp gage to check various places on the radiator. If it is flowing properly the temp on the core will be fairly uniform all over the radiator. If you find cooler places, take the radiator out and flush it to make sure there's not debris in it. If nothing flushes out, have it professionally cleaned.
Also, small things can make big differences. On my first Cobra (a big block 460) I had a similar problem, and solved it by sealing the fans very closely to the radiator...my overheating problem at idle was caused by air loss around the shroud, and I only had a 1/4" gap!
BTW, 70% water and 30% coolant is a fine mixture, that is not your problem. If it was a faulty pump it would overheat worse at speed. Advanced timing isn't the problem, although you ought to have yours all in by maybe 2500 instead of 2000 rpm. Retarded timing can cause overheating, but yours sounds fine.
Keep us posted, someone here will help to figure it out.

Thermostat is backwards?
Is small hole in thermostat on high side when installed to allow air to escape?

A good puller fan , 2800 cfm should help . Also antifreeze will raise the boiling point . Do a radiator flush first . They also sell hi flow thermostates and water pumps . My 427 side oiler runs between 190 and 210 F .
Peter

1)Me thinks you got that backwards.A restrictor plate acts like there is no T-stat.And it will give you a hint about where it's(the problem) is happening.

2)In the absence of other "factors",i agree.


3)I understand your logic,but Deathcool is the only coolant that i know of that you really,really,REALLY don't want in your motor.ANY motor.Any other glycol based stuff is fine.

If things start pointing at the radiator,a "Home type"radiator flush won't fit the bill.Take the radiator to a shop and make sure you tell them that there was Deathcool in it.

Just to recap, the fan is 3600 cfm, the t-stat is the cobra Valley 180* hi-flow which I have confirmed is in correct. I drilled an 1/8" hole in the top.

By restrictor, if you mean something that partially but not completely restricts then I see your point. I thought you meant a complete restriction. I think I now have two issues, the original problem of cool on the road but warm at idle, and now the problem casued by the shroud, which makes it heat up indefinitely without ever coming back down. I am still confused as to why the shroud has hurt instead of helped, so I will probably regress to the prior point and remove it next. Lucky for me, a new radiator shop just opened a mile east of me and I think I will pay him a visit and get an expert to confirm exactly what this radiator is and what I might need.

One thing I'd like to confirm with those of you who have an expansion tank...I removed the cap and let it heat up to t-stat opening. the flow is churing and moving but almost belching and vomiting water out in spurts. Look at this clip I just shot right after the t-stat opened and tell me if this looks right for an FE (Cobrabill, don't watch, its a DexCool volcano):

el, when you go to the radiator shop, ask them (if they don't suggest it) to test the coolant for combustion byproducts. If you have a slight head gasket leak you could get the volcano in your video, with a small amount of combustion gas leaking into the coolant. If so, the superhot combustion gas could add heat faster than the fan could take it away, and maybe at speed it has enough airflow to keep it cool(er)?
Just a thought...

Yes.Now we're on the same page.Take an old NFG T-stat and cut the guts out of it.That should suffice.