Overheating question

[BillyDeluxe]

Hi guys,
I have a bored 350 out of a 1980 C10 truck in my 65 short stepside. During the summer months I always have the same problems since a few years now.
Always when I get stuck in the traffic the engine starts overheating. As soon as you move again the temp in going down quickly.

What I've tried so far:
-I switched to the factory stock 3-row Harrison radiator (had something different before)
-switched thermostat serveral times (tried 160, 180 and high flow),
-switched from a 16" belt-driven fan to a 19" belt driven fan,
-tried with and without electrical fan (yes it's better with electrical fan switched on but I want to go without - it must be possible!)
-because of a blown head gasket I cleaned both heads last year and checked all the water channels - nothing suspicious
-I bought a stock shroud but the new 19" is too big for it, surprise!


What I would do next:
-I would buy a brand new radiator (maybe 4-row desert edition) - hopefully the brackets still fit for the bigger one
-I would give my current radiator away to let it clean and give it a new net
-I would swap the water pump to a Edelbrock or Stewart high-flow pump to get more flow into the system


What do you guys think - what would be your next steps?
Thanks
Andy

[RUSHNBOBO]

Originally Posted by BillyDeluxe

Hi guys,
I have a bored 350 out of a 1980 C10 truck in my 65 short stepside. During the summer months I always have the same problems since a few years now.
Always when I get stuck in the traffic the engine starts overheating. As soon as you move again the temp in going down quickly.

What you have is the perfect example of airflow issues.

--as a rule of thumb when you only overheat sitting still and or slow speed...it's almost always air flow and not coolant flow....as soon as you get rolling it cools off ?..... why ?.....air is flowing naturally through the grill without the need of a fan to cool.

--first, your going to need that shroud back ........ it forces the the air to be pulled through only the radiator and not around it. even going back to a smaller fan would be better than no shroud at all with a larger fan.

--next make sure there's no obstruction in front of the radiator...did you maybe add something to the radiator support area

--your fins are probably clean enough or it would overheat all the time

--now what type of fan do you have?...The fan setup that I use and probably can't be beat in pulling huge amounts of air is a factory type thermal clutch fan with a diameter that is as close to touching the shroud as you can get. These despite what you might hear these use very little horsepower until they are needed...they basically are freewheeling when enough air is flowing through the grill because the thermal sensor, mounted on the front of the clutch, will disengage. When things warm up such as stopped or slow speed the aiflow through the grill is non existant and the sensor spring will begin to rotate the opposite direction....engaging the fluid clutch automatically

--concentrate your efforts on getting more fan air flow.....your overheating symptoms tell me it's not coolant related

--look for a factory fan with an aggressive pitch....with the clutch it won't affect you performance ....that's the beauty of them.

--if this still won't cool the engine down leave the clutch fan setup in place and look into the bigger 4 row..... a larger radiator will help cooling in all situations stopped, cruising and under load

[BillyDeluxe]

Hi and thanks for the perfekt description of my problem.

Just to answer a few of your questions:

-I have a Flex-a-lite 19" steel blade fan
-in front of the radiator is just the tranny cooler nothing else

I immediately ordered a new fan clutch on ebay US, the fan itself (smaller than I have now, I believe 15" to 16") and the bolts I try to get at my local parts dealer.

May somebody tell me if the 4-row raditor will fit into the stock brackets?

THX

[198plus]

Also check your timing and make sure your running a vacuum advance.....So many times people think it's the cooling system when it's not........Here's a good read on the subject.

http://www.chevelles.com/forums/show...timing+heating

[rideblue00]

I agree with 198plus on timing. And rushnbobo. Get a fan with a higher blade pitch. Your trans cooler may be constricting some flow. So the shroud is also a must. Also a bored engine has thinner cylinder walls. So that means hotter sooner. But i think air flow is the culprit.

[oldtrux]

i agree with airflow but disagree with thinner wall story!

[RUSHNBOBO]

Originally Posted by BillyDeluxe

May somebody tell me if the 4-row raditor will fit into the stock brackets?

THX

4 row brackets are wider, because of the extra thickness of the core and tanks ....but there not all that expensive.....

You may already know this but your "flex type" fan will not work with the thermal clutch, they use a dedicated fan that bolts directly to the clutch.....the bolt circle is considerably larger. Also there is limited options in aftermarket fans for clutch mounts, I believe that Flexalite does make them now. If not there are plenty in the wrecking yards, look for something from a truck or fullsize car...as they are more likely to have the pitch your looking for. I believe that all early GM clutch fans have the same bolt pattern ....but measure your new clutch bolt circle to be sure.

[rideblue00]

Originally Posted by oldtrux

i agree with airflow but disagree with thinner wall story!

lol, why is that? Thinner cylinder walls conduct heat faster. I was citing that only as part of the problem( a very small part) anyway.

[oldtrux]

he mentioned his engine was bored,i didn't read that it was bored 80 over or something.i'm just thinking his problem is air flow or perhaps timing is way out.i guess maybe a very thin wall wouldn't be able to dissapate heat as good but i think in very rare instance that a bored engine is the cause of a hot running engine.just my thoughts.

[rideblue00]

I agree on the timing and airflow as well. The bore thing is like a sidenote.

[corvettejim1968]

Originally Posted by BillyDeluxe

Hi guys,
I have a bored 350 out of a 1980 C10 truck in my 65 short stepside. During the summer months I always have the same problems since a few years now.
Always when I get stuck in the traffic the engine starts overheating. As soon as you move again the temp in going down quickly.

What I've tried so far:
-I switched to the factory stock 3-row Harrison radiator (had something different before)
-switched thermostat serveral times (tried 160, 180 and high flow),
-switched from a 16" belt-driven fan to a 19" belt driven fan,
-tried with and without electrical fan (yes it's better with electrical fan switched on but I want to go without - it must be possible!)
-because of a blown head gasket I cleaned both heads last year and checked all the water channels - nothing suspicious
-I bought a stock shroud but the new 19" is too big for it, surprise!


What I would do next:
-I would buy a brand new radiator (maybe 4-row desert edition) - hopefully the brackets still fit for the bigger one
-I would give my current radiator away to let it clean and give it a new net
-I would swap the water pump to a Edelbrock or Stewart high-flow pump to get more flow into the system


What do you guys think - what would be your next steps?
Thanks
Andy

i bought a 2 one inch core Be Cool radiator , put a 195 thermostate and added water wetter. my temp before was about 229-242 and in stop and go it was 268 now it NEVER gets above 212 and i live in Phoenix Az.

[RUSHNBOBO]

Originally Posted by corvettejim1968

i bought a 2 one inch core Be Cool radiator , put a 195 thermostate and added water wetter. my temp before was about 229-242 and in stop and go it was 268 now it NEVER gets above 212 and i live in Phoenix Az.

Those Be Cool radiators are definitely top shelf .....and the price tag shows it.

I think if Andy.... tries the obvious (inexpensive stuff) to get his low speed airflow up, as well as getting the timing optimized. It may very well be enough.

Like I said if everything is setup and working like it should and it still overheats, the radiator upgrade is the only thing left.

Another option to the high end aluminum radiators is to go with a 4 row brass, copper replacement...this is what I run w/ a 160 degree thermostat never seen the needle move over 160, ever ...no matter how hot it is. Just having more liquid in the system no matter what it is will make anything run at lower temps. It's all about the "heated" volume of liquid is always trying to return to ambient air temp once it leaves the hot surface ...so the more volume you have, the easier it will be to keep cool.

If you had a large enough container of coolant ....say 30 gal. ....you could hook up your engine with no fan or radiator, and it would never overheat. Some engine dynos are set up this way. There is so much volume of liquid in the container it can't possibly stay very hot before it recirculates back to the motor. this obviously is not practical in a vehicle....but demonstrates the principal.

One more easy thing you can do Andy....is run the least amount of antifreeze as possible ...15-20% if your climate permits. "antifreeze coolant" is a misnomer ...it has very poor cooling properties....straight water out-cools all antifreeze mixtures, but running plain water is obviously not good for the motor , long term ...it has no lubricating or anti corrosive properties and also has a lower boil over point. So just keep the ratios to a minimum ....I run around 15% in a mild climate which never sees freezing temps, works great.

[padresag]

a 50/50 mix of anti-freeze and water raises the boiling point 18degreesF. also depends on what he is using for a pressure cap and if it is functioning properly. he will notice a difference with the stock fan and a shroud on there. the shroud and fan also depends where the fan is in relation to the opening of the shroud. as he is running a later eng he will have the long w/pump on there, but with a shorter spacer should be able to compensate. the next part of this is where is the eng sitting? Is it in the frt holes or the rear holes on the frame. for the right relationship for fan and shroud it should be in the rear holes. guess this is why they let engineers design these things in the first place. so many haphazard things happen with a lot on installations in these vehicles without the thought of the original installation or what the relationships are
ron

[BillyDeluxe]

Guys,
what I will do next is going down to a 16" fan with clutch. I will get back this original shroud I have to maximize air flow through the radiator. If this doesn't work I will go for a 4-row brass, copper replacement for my radiator. The only difficulty I see is where to get this wider radiator mounts from. Can somebody tell me where I can get it from?

It's not just going to a wrecking yard. Don't forget I am living in Germany guys. We have a number of around 50-80 Chevy trucks from the years 60-66 running in the whole country guys! If I would live in the states I would be in paradise for parts and cars! But shame on me. I've never been there.

By the way: I want to visit the States in about 3 years. Maybe I can meet somebody of you guys.

Andy

[RUSHNBOBO]

Originally Posted by BillyDeluxe

Guys,

The only difficulty I see is where to get this wider radiator mounts from. Can somebody tell me where I can get it from?

Don't forget I am living in Germany guys.

Andy

Have you checked for parts suppliers in Great Britain?....I know they are big into American classic cars....not sure about the trucks though.

I'll start looking around for upper and lower 4 row brackets shipped to the EU... we'll find someone, I'll send you a PM with info tomorrow.

TTYL .....Dan

[BillyDeluxe]

Originally Posted by RUSHNBOBO

Have you checked for parts suppliers in Great Britain?....I know they are big into American classic cars....not sure about the trucks though.

I'll start looking around for upper and lower 4 row brackets shipped to the EU... we'll find someone, I'll send you a PM with info tomorrow.

TTYL .....Dan

Hey Dan,
that's great! Thanks a lot!
Andy

[oldtrux]

hey andy,i spotted one of them on vacation a couple of weeks ago!i think this one was somewhere in belgium.it was my first trip to europe,we did 4 countries in 18 days.what an experience!!absolutley beautiful!i now understand that high performance cars are made for europeon highways.we had our opel rental up to 200kph and audis etc blew by us like we were standing still....amazing...good luck with your project,cheers dan

[BillyDeluxe]

Hey Dan,
that's right Germany ist one of the countries in Europe where you have even no speed limit on most of the highways. That's very cool. If you come to other countries as a German driver you always have to slow down!
The only sad thing is that you are always very much slower than all the others with your Chevy truck on German highways. haha!

Cheers! for helping me with the radiator mounts

[brawley]

ive heard if your running headers and temp. sending unit is in block it could show higher than actual temps ?? not sure but I am going thru a similar situation right now and am trying to lower temp. at idle.

[BillyDeluxe]

Originally Posted by brawley

ive heard if your running headers and temp. sending unit is in block it could show higher than actual temps ?? not sure but I am going thru a similar situation right now and am trying to lower temp. at idle.

Hey brawley
what I know is that headers are producing a lot heat around the engine, yes. That's why I am using cast iron stock headers. I don't need even more temperature ;-)

[63MOUSE]

i bought a 4 row radiator about a year ago from u.s. radiator and all stock brackets, top and bottom fit. no wider brackets needed

[Slow Build]

Would a coolant recovery system help out at least a little bit? I know it's not the answer to the overheating problem but I would think it would help keep the radiator full so you have the maximum amount of coolant available. I don't have water temp issues but my radiator takes a leak sometimes just after a drive. I just watch my fluid level and fill as needed. I'm planning to put a recovery tank on mine.

I think your on the right path though. Getting more air flow will probably take care of your overheating problem.

[RUSHNBOBO]

Originally Posted by 63MOUSE

i bought a 4 row radiator about a year ago from u.s. radiator and all stock brackets, top and bottom fit. no wider brackets needed

They have high quality radiators, and have 2 different 4 row radiators for this truck one uses stock size brackets and the other is 1966/w air and uses wider 3 inch bracket. Also each of these have 3 different core options. Prices are from around $425.. to $560.. Also one 2 row all aluminum for about $390.00

They don't sell retail from there site .....where did you buy yours ?.....all of my local shops don't ship internationally.

[RUSHNBOBO]

Originally Posted by brawley

ive heard if your running headers and temp. sending unit is in block it could show higher than actual temps ?? not sure but I am going thru a similar situation right now and am trying to lower temp. at idle.

interesting ....you could try to diagnose this by maybe wrapping the header tubes nearest to the sensor and compare readings.

[BillyDeluxe]

fantastic guys!
I will search for that 4 row which fits into stock mounts. I am sure that will solve my problems. hopefully these guys ship to Germany. I'll keep you updated.
A very nice place here. I am happy about all your help.
Cheers!

Andy
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