[Mazrolet]

Hey all this is my first time posting on this forum but that could be due to me not owning a Camaro. I have a problem with a 350 Chevy motor overheating, reading other posts you guys have a lot of interesting suggestions that might help my situation.

Here is the scoop in 2001 I had a 350 Chevy put in my 1991 Mazda B2200 pickup you ask why well it’s a show truck and I needed it to look pretty. The motor is bolted to a turbo 400 trany and cooled by a 4 core Griffin aluminium rad with dual Flex-a-lite fans. Also I swapped out the rear end for a Ford 9 inch to get the right gear ratio.

When the motor was built it ran around 180-190 degrees but it was set very rich for break in time. The next few years I didn’t drive it much because it always would run around 220 degrees and I got tired of keeping the heat on in the summer, did I mention I only drove it in the summer. Now I can only drive it at night on those cool summer nights or with the heat on even that gets the temp up to 220-225 degrees.

I have changed the thermostat several times trying different ones to see if this would help and I ended up just running an open thermostat because nothing else worked. In 2002 I had the shortie Hedman headers wrapped but then was told about horror fire stories so I took it off. In 2005 I got the headers ceramic coated but didn’t notice a drop in temperature.

This is what I know the trany should have been a 700 to give me the overdrive also because of the custom truck the front bumper cover is not letting that much air through the front. Before I go and change the trany and front end of my truck I want to know if there is anything else I can do to try to keep this motor cool.

I appreciate the comments.

 

[DjD]

Hi Maz...

I think you need to go back to the basic's, install a 180 stat and be done with playing with it. If it opens and the temp gets above 180 it isn't going to close so unless it isn't opening it's not part of the equation. Next we really needs more info from you. It sounds like an air flow through the core problem but until you can tell us when the engine gets hot on you don't take that for gosipel...

Usually knowing that temps climb when idling but drop off when moving indicates your fan(s) are not pulling enough air through the core. From there if it doesn't cool down at 60 mph the core may well be blocked and not getting enough flow through it. Most vehicles with restricted grills use some form of baffeling to maximize air flow to the core. You may need to fab up something along this idea.

 

[Mazrolet]

Thanks DjD the trucks in storage but I'm heading that way so I will start her up and see what the Temp is like at idle. I will put the 180 in.

It get's hot usually when driving but let me see what the temp is at idle.

 

[Steptoe]

As DJD says
We had a very nice cinversion of a 300z with a 350/350 turbo in the workshop a while back....and that ran hot.
After sorting a few tuning problems like curve/carb...was still hot, thu ran a little cooler on the open road at higher speeds.
The trans cooler was mounted in front of the raditor...this was relocated to the side behind the grill (well if it had a grill as we know it)
This helped.
The licence plate was mounted over the front lower grill. Moving this helped a little more, as did using a second electric fan so that now most of the grill was also fan cooled
We knew the raditor was big enough and had reasonable air flow...
The raditor was flushed and flow checked at the start...
So pulled the header tanks off, manually cleaned the cores...
Problem solved...would hit 195* in heavy trafiic

This 300z was impressive, even thu the engine was basically stock...
That engine compartment was made for a SBC and trans. The interior gear stick consol etc ...everything was stock nothing had to be changed.

 

[Everett#2390]

Using a high-flow thermostat would probably help, MRG-4364, Mr. Gasket p/n.

 

[Fred Ficarra]

Are you relying on the stock fan configuration? I'm sure the flexalite is a clone of the factory system. That means you need a shroud. They're vital. No more than 1" clearance from the blade tips and make sure the blades are just inside the shroud for good suction. God I love that word! Good luck. How about some pictures?

 

[Mazrolet]

Ok after runing the truck for 30 min the temp only reached 150 this of course is in cold weather at 0C. I didn't change the stat yet so it's still open.

Steptoe my trany cooler is mounted behind the rad so I guess that's a good thing. The Edelbrock Carb does need a little tuning which I'm sure will help a bit.

As for the fan shroud that's a good one the engine bay is so small the fans are mounted to the rad (without shroud). The crank pully is so close to the rad you can barely fit your fingers between the rad and pully. There is just no way to have a shroud in my setup.

Do you think getting rid of the dual fans and going with one 12" fan might be better?

I will try to post some pics.

 

[BlackoutSteve]

You are obviously not exchanging enough heat, which could be not enough airflow, radiaitor capacity, or not enough water flow.
It sounds like your radiator and the air flowing through it should be OK but..

What is the condition of your waterpump? Perhaps the impeller is shot.
Do you have the correct sized pulleys so it's spinning fast enough?
Is there the possibility of a head gasket failure? -Are exhaust gas bubbles forming at the radiator cap?
Are you losing water/pressure from a bad cap?
If you have a recovery tank, do you have the correct recovery cap?

 

[Mazrolet]

 

[Mazrolet]

 

[DjD]

From what I'm seeing you have a very small grill area, twin electric pusher fans and a portion of your core blocked by a trans cooler. Your problem is air flow!! Make sure your fans are moving the air the right direction. If they are, I'm thinking your in for a spending spree...

You have a very thick core and having the fans mounted on the outside of the engine compartment and pushing air through the core isn't the way to go. The pusher fans actually block flow when the car is moving as they physically block the core. The trans cooler doesn't help either, mounted low and on the outside of the rad core would be a better location for it.

You are between a rock and a hard spot here... What I would do is find another rad that's not as thick as that 4 core. Air flow through a thinner core will increase greatly. No room for puller fans so get the most cfm single electric fan you can find, make sure it turns the right way to push air through the core. Then replace your trans cooler with something you can mount below the rad core, there are some cool units that are about 2" round and different lengths that won't block your core. You could even get an core with a trans cooler in the tank.

With those changes if you are still not running where you want work on some ducting from under teh bumper up into the core and try blocking off the air gap from the radiator back on th eunder side of the car.

 

[1511tim]

I am not sure, but I think it is not too hard to pull that grill out "just temporarily" and drive for a while, mabey even the plastic bumper guard. If it runs cool, then you know you need to open it up somehow. A lot of things can cause overheating, but I can see that not much air can get through that grill. :beers:

 

[1511tim]

Dont forget that the incoming air also needs to get out in order for there to be good flow.:beers:

 

[kustomwerker]

you could try a cowl hood...air will pass much more readily ...as 1511tim suggested,if it can get out , your temp might drop...i think the restrictor is a bad idea especially in your case, as water doesnt have enough time in the radiator to cool off...you could also try water wetter...you can get it at summit or jegs...i believe it improves the conductivity of the water so it sheds heat better...

 

[Steptoe]

Steptoe my trany cooler is mounted behind the rad so I guess that's a good thing.

As DJD says above behind/infront, it still restricts...
I have mine mounted below the raditor and attached to, leaning back to the bottom of the engine.
The fans need shroud to work...look at the fans inside your computer....without shrouds most of the air spills off the end of the blades rather than being directed in the direction needed.
DJD mentions this before moving onto restrictions due to the size of the radiator..I agree...
Even if you use a less restricting radiator with your current setup the chances are you will still have the same problem....sorting the fans 1st has a very good chance of sorting without going to a new raditor.
Your grill size...that may or may not enable enough flow...looks close either way...so sort the fans.
can you duct up from the bottom vents also?

Ok after runing the truck for 30 min the temp only reached 150 this of course is in cold weather at 0C. I didn't change the stat yet so it's still open.

Slip a sheet of newspaper over the grill or front of the raditor, get the temp up then see if it drops....

Is there the possibility of a head gasket failure? -Are exhaust gas bubbles forming at the radiator cap?

Check out the local workshop, get them to run a HC gas test on the raditor...
Further info in other posts....If this is positive, no matter what you do, a leaking head gasket will still run it hot.
A 3/16 hole drilled in the thermostat will give u a high flow thermostat (a Smokey trick)..do not run without a thermostat, u can get into a situation where the water flows thru the raditor to fast to cool...again an issue Smokey addressed yrs ago and an issue I have had to address.
Replacing the thermostat and cap is also worth a try...very common issue.
Have you checked the sender is reading right?
A thermometer in the top of the radiator with give a

close

reading to the gauge +/- 5* or put in a electic jug with a thermometer and heat up the jug.
These are all low cost/labour issues before getting into bigger fixes.

 

[Mazrolet]

Thanks for all your help I will put the 180 stat back in also try to find a signal fan with a good CFM. I will look for another place to mount the trany cooler to move it away so the air can flow better.

Do you know what kind of car would have a good fan that I could probably get from a wrecker?

I do have another grill that's cut out but it only helps a little. As you can tell the rad goes all the way down to the bumper so the grill is only half the rad. The fans are moving in the right direction and as you mentioned you can feel more air flow at the sides of the rad rather then all over. I have checked the temp in the rad and it's dead on to the Autometer temp gauge.

Cowl hood great idea but with a pearl paint job I would have to repaint the whole truck.

 

[Fred Ficarra]

One more thing,,,,,,

Nice ride!

 

[Mazrolet]

Thx Fred.

 

[Mazrolet]

Hey guys any word on the fan what car I can use it from?

Also I believe when the 9" rear end was installed they put a 308 gear in it. I'm running 18" wheels with 215/40ZR/18 rubber. Next time I go to the storage I will rotate the wheel to confirm the 308 gear. Any suggestions if I should change the rear end gears.

Thx