350/ Overheating

Black Dog · 08-14-07, 02:08 PM

Things I have done: New aluminum radiator from Man-A-Fre (stock size) high flow 160' thermostat, new water pump, tried two different manual fans with aid of small electric fan, different shrouds, burped system, 20 pound cap, timing is dead on, and finally put in a different 350. any hills or idle will run to 230' before I sut it down. It really hates to sit and run at all with out overheting. My question is if there is a chance that the water is running through the motor to quickly??? I have acually tried three different thermostats. If it is running through the radiator to quick what do I do to slow it down????? Or any other ideas would help. By the way the motor is not pumped up at all.

FJBen · 08-14-07, 02:33 PM

195 Degree thermostat...

what fan? big clutched chevy fans?

Taurus electric fan?

how's your engine placement? Too far back can cause some issues with heat.

Dynosoar · 08-14-07, 02:34 PM

Do you have a shroud? To slow down the flow you can put a restrictor plate in, or use a standard thermostat vs the high flow. I have had very good luck with my Volvo electric fan, and I know others have used this or the Taurus/MarkVIII fan with good luck. Do you have an automatic trans or stick? If auto how are you cooling the trans? s the radiator the highest point in the system? Is your gauge accurate (test with thermal gun on radiator input). It is difficult at best to solve these issues without the proper information.

Dynosoar

Downey · 08-14-07, 02:55 PM

Most Chevota over-heating is caused by:
(a) Marginal radiator. Has the MAF alum rad got enough gph flow rating?
(b) Wrong thermostat. Yours sounds fine.
(c)Electric fans or flex fans. Electric fans in themselfs are not poo-poo, most people simply do not use anywhere near enough fan. Electrics need to be 3500 cfm minimum!!!!! Flex fans----joke, joke, joke
(d) Engine runs cooler when there is a fan shroud, BUT BUT BUT engine runs coolest when zero percent of fan is inside the fan shroud. (SAE test results, I won a law suit on this back in the 80's)
(e) Engine too close to firewall. These rigs will run 240 degrees on the coldest day of the year.

Black Dog · 08-14-07, 03:00 PM

Gauge is acuurate (tried two) turbo 400 trans with cooler but not blocking radiator, fan is flexlite orderd from summit racing , it isn't a flex fan though. Engine placement is good and there is only 1" between radiator and fan.

Black Dog · 08-14-07, 03:02 PM

Dist. is about 3" away from fire wall. Explain how much of the fan should be in the shroud, zero or half way?

Cruisertime · 08-14-07, 03:37 PM

If youre running a carb check that your not running too lean. Also, see if your cooling system doesnt have air in it. I know you burped it. But do a double check....

Shawn Russell · 08-14-07, 03:44 PM

I hadthe same set up as you (Man-A-Fre Alum) and it was not enough. I sent the $$ hoping that the rad and shroud would fix it. You have to go to a larger rad. If you are looking for easy install, you can get the larger rad setup from Man-A-Fre also. That one does work. I do not understand why they still sell the stock size option. They know it does not work, and told me so when I called back to get the larger version.

Shawn

Black Dog · 08-14-07, 03:53 PM

I was afraid that I might hear this!!!! When I bought that radiator I was sceptical but I would have had to move a whole bunch of stuff to fit bigger one in. What really pisses me off is why do they sell this thing? They told me it would work with no problems!!!!!!!!

dgangle · 08-14-07, 04:21 PM

Boy you have hit upon a topic of debate. There are some that say the rad you have is adequate for the task, many more that say it isn't. Based upon my experience, I suggest a GM clutch fan from something big....caddy, blazer, suburban, etc. I use a thermal clutch fan from '84 1 ton Chevy with 454, AC, etc. Next is a properly positioned fan in a good shroud. By 'good shroud' a mean one that allows full flow of air to the core, not a flat plate with a hole in it that blocks 25-40% of the core area. From what I have read, input from others who have successfully cooled a Chevota and experienced myself, the fan needs to be positioned 1/2 in, 1/2 out of the shroud. I run an inexpensive SBC water pump with a no-frills $4 180F thermostat on an aluminum radiator with around 400 in2 area I had custom built by Superior Rad in MI. It has two rows of 1" oval tubes. Regarding engine placement, I have always used the recommended Downey/Advance Adapters dimensions so the engine is out away from the firewall. Last, or maybe first depending on how you look at it, is a quality, accurate gauge.

dgangle · 08-14-07, 04:23 PM

and some more

cpratt · 08-14-07, 04:43 PM

I haven't had any cooling issues with the setup the PO did. Standard radiator with a good shroud and good placement. The fan is about half way in as dgangle said. I'm also running a 180 thermostat and rarely see it rise to 190, even in when it's in the 90's out here.

The PO mentioned he tilted the radiator back a little so the fan filled the shroud better.

FJBen · 08-14-07, 04:46 PM

I tried a big mechanical fan from a caddy, and it hit my lower radiator hose

Personally, I'd rather run the mechanical fan...is there a little smaller one that might work? or a reason why that fan would interfere with my lower hose? I currently run the Taurus fan.

I'm using the AA mounts.

dgangle · 08-14-07, 05:23 PM

I too have the AA (Transadapt) front motor mounts. You could lower your radiator (preferred but harder/time consuming) or trim a small, equal amount from every blade (relatively easier but then there is the issue of balance and the possibility of looking like a hack....).

dgangle · 08-14-07, 05:36 PM

cpratt,
That looks like a good shroud. I bet that solid fan sounds like a 747 at take-off! Have you tried a clutch fan? I was impressed with how quiet mine was as I had a solid fan at one time. It would suck nuts and bolts off the garage floor!

One suggestion.....Go get a Gates 20416 top hose and get rid of that universal one. See

http://forum.ih8mud.com/showthread.p...gates+top+hose

posts 5 & 11. Fits like it came from Araco that way.

You may need a more angled thermostat housing, though.

FJ40_owner · 08-15-07, 01:55 PM

I have a carbed 350 running a stock LC radiator and Turbo 400 trans. I also experienced cooling problems. I installed a 2500 CFM electric fan and my engine would overheat as soon as the 195 stat opened.

I was very frutrated and ripped the e fan out. I took the radiator to a shop and had it rodded out. I kept a close count of how many water lines were clogged. There were ten clogged out of I think 40.

I put the stock rad back in with a six blade mech fan and no clutch. My radiator man said to install the fan just inside the shroud and that is what I did. I run on the 190 stat 90% of the time.

During high OSA (>90) and driving very slow the temp will get up to 210 or 220. I just run the heater and this seems to work fine.

A side note. I thought the Efan would be the answer to my problems. It was not. The old fart radiator man had disdain for Efan. I followed his advise and my cooling problems went away.

My .02.

JB

Black Dog · 08-15-07, 05:03 PM

Thanks for all the replys. The shrouds I have built for it look like crap compared to those. I will have to copy those and try it again!!! I also like the idea of a clutch fan. I'll give the old college try and report back

dgangle · 08-15-07, 05:03 PM

having to run your heater as your remedy hardly figures as a solution. you need a larger radiator, period.

dgangle · 08-15-07, 05:07 PM

Quote:

Originally Posted by Black Dog

Thanks for all the replys. The shrouds I have built for it look like crap compared to those. I will have to copy those and try it again!!! I also like the idea of a clutch fan. I'll give the old college try and report back

I made mine out of cardboard. Some sugegsted I should have fiberglassed it and called it good. I found a local old-school stock car body fabricator and he used it as a template to make it from aluminum.

dgangle · 08-15-07, 05:10 PM

more

Black Dog · 08-15-07, 05:13 PM

Template is a good idea, I don't think I can make it that pretty. Thanks again I post on the progress.

dgangle · 08-15-07, 05:34 PM

Quote:

Originally Posted by Black Dog

Template is a good idea, I don't think I can make it that pretty. Thanks again I post on the progress.

Depending on your skills it's really not that hard....and very forgiving. Try it, it's only paper, a box cuttter, straight edge, a sharpie, some masking tape and time. Finding one in a boneyard is, well, like finding a needle in a haystack and always a compromise.

warpdriv · 08-15-07, 07:59 PM

When I was having overheating problems, a 195 degree thermostat was the cure. My problem was the water was not staying in the radiator long enough to cool down.
HTH,

edgemonster · 08-15-07, 09:50 PM

The only thing that has made me happy is my Be Cool radiator with standard clutch fan. I got mine from summit (#bci-62167) with the 1-ton trannny cooler built in. I tried to reuse my shroud but wouldn't work. Have been running the unit for the past 6 months and have yet to see my temp gauge surpass 200. Regular driving it never gets past 180. I can actually watch the gauge when the termosat opens and see the temps back down. Pricey but I'm thrilled. anyone want a 2 piece shroud? you pay freight.

Black Dog · 08-16-07, 03:23 PM

Quote:

Originally Posted by warpdriv

When I was having overheating problems, a 195 degree thermostat was the cure. My problem was the water was not staying in the radiator long enough to cool down.
HTH,

I'm a little confused on this? Once the therm. opens, it's opened. I'm not disagreeing I just don't understand?

inkpot · 08-16-07, 03:57 PM

Quote:

Originally Posted by FJBen

I tried a big mechanical fan from a caddy, and it hit my lower radiator hose

Personally, I'd rather run the mechanical fan...is there a little smaller one that might work? or a reason why that fan would interfere with my lower hose? I currently run the Taurus fan.

I'm using the AA mounts.

Howdy! Any good radiator shop can fix that problem. I had my lower outlet moved from the back of the lower tank to the bottom, and replaced it with a 90 degree turn. It is now about 5" from stock. I can run 20+ inch fan with no clearance issues. John

edgemonster · 08-17-07, 09:37 AM

Black Dog here's a good explanation of what's happening with the thermostat.

http://auto.howstuffworks.com/question248.htm

mminter1973 · 08-17-07, 10:07 AM

Here is a major part of why a lot of you, including myself are experienceing overheating, the Camshaft. What you say? It is true if you have a stock or small duration cam your motor will overheat a lot faster that a motor with a bigger cam. Heres why. A stock or small cam has less duration and valve overlap which causes higher cylinder pressures, this in turn causes more heat to build up in the engine rather than expelling the pressure, aka compression letoff. A bigger cam will bleed ogff more cylinder pressure therefore allow your engine to run cooler.

You dont have to run a rattle the windows saturday night drag cam but a cam with a little more duration and overlap will let a lot of the hot gasses out.

I know this because i have experienced it in case some of you are wondering.

dgangle · 08-17-07, 02:35 PM

I have had mild to wild cams in 350 & 400- powered SBC in FJ40's and all have run hot...230+ with an inadequate radiator/fan/shroud. I have not personally experienced of which you speak. It sounds a little pie-in-the-sky.

In my experience cooling a Chevota has everything to do primarily with radiator size and air movement. I put Water Wetter, oil coolers, Motor Honey, Slick 50, snake oil and prayer all in the same category.