[eric32]

Hello guys, I am having a sort of problem that I can't figure out. Fist off this is sitting in an 86 s 10 I have a 350 chevy with iron heads and block. I am using a regular fan not electric. No schroud,fan sits only about three inches from the radiator. The intake is aluminum. I did have a four core brass radiator that came out of full size chevy truck early 80's. I have a 160 thermostat and a high volume water pump.

Last summer it ran around 160 to 170 all the time never got to 200 on the highway. It would see 200 rarely if I sat there and idled and was in stop and go traffic and did not get moving but once I got going it did ok temp wise and was steady at 170 to 180. Ok I just installed a griffin universal radiator with similar dimensions as my brass radiator. Its a two core with 1 inch rows and the size is 32 inches wide and 16.5 inches high core height. The old brass one was only 1 inch taller core height wise but the same length. Ok I just finally got everthing back together after changing out my gear drive for a new timing chain and finally got it up and running.

Ok there are no leaks and I checked everything. Ran it till I needed to totally fill up the radiator after the stat opened up. The temperature was running the same as it did recently with my old radiator. It went up to 160 then the stat opened up and the temperature went down to about 150 then got up to 180 and stayed there and then want to kind of creep up to 190 and almost 200. It goes kind of back and forth and I get nervous with it doing that. I have no air bubble that I know of. But I don't want it too run 200. It always ran at 180 and stayed steady last summer.

Thermostat is a high flow non restrictive for high volume water pump. I don't have a shroud on it yet. I am going to have my dad custome make one from some sheet metal. Any advice.

[Jmark]

200 is not hot. It's actually good for the engine to be up between 200 to 220. My suggestion would be to install some kind of fan shroud. It will help emensley.

[ScoTFrenzel]

There is no way a GOOD 160 thermostat will allow an engine to run cooler than 160. If your gauge is saying 150, you have a gauge problem.

I suggest you take some infrared thermometer readings and find out if your gauge is reading correctly. The fluctuations could be a sending unit or gauge problem.
A radiator should drop 25* inlet to outlet under any conditions.

Most people don't realize that with a big (copper or aluminum) radiator you need to overdrive the water pump and/or use a high flow water pump. The water flow must be fast enough through the tubes to create turbulence and break the laminar flow of the coolant or the radiator will NOT cool like it is suppose to. This is why so many hot rodders install bigger radiators and still have cooling difficulties.

You definitely need a stock type shroud under any circumstances.

[eric32]

Well I do have a high volume water pump on my engine at this time along with a high flow thermostat non restrictive. It does a lot better cooling wise then what it did before with a previous build but I don't think it should move up and down temp wise like this. Thanks for the comments.
Eric

[ScoTFrenzel]

The first 3 high flow stats that I installed came from 3 different sources and all 3 failed in a short time. The replacement high flows have been fine. All Robert Shaw.

Thermostats do not just fully open and fully close instantly, but partially open to the degree necessary to maintain the temperature.
With the fluctuation you have, I would consider getting another high flow thermostat.

Also 2 small holes drilled into the stat allow a small flow all the time and helps purge air when filling the system. Check out Stewart or Moroso for pictures.

[oldbogie]

Originally Posted by eric32

Hello guys, I am having a sort of problem that I can't figure out. Fist off this is sitting in an 86 s 10 I have a 350 chevy with iron heads and block. I am using a regular fan not electric. No schroud,fan sits only about three inches from the radiator. The intake is aluminum. I did have a four core brass radiator that came out of full size chevy truck early 80's. I have a 160 thermostat and a high volume water pump.

Last summer it ran around 160 to 170 all the time never got to 200 on the highway. It would see 200 rarely if I sat there and idled and was in stop and go traffic and did not get moving but once I got going it did ok temp wise and was steady at 170 to 180. Ok I just installed a griffin universal radiator with similar dimensions as my brass radiator. Its a two core with 1 inch rows and the size is 32 inches wide and 16.5 inches high core height. The old brass one was only 1 inch taller core height wise but the same length. Ok I just finally got everthing back together after changing out my gear drive for a new timing chain and finally got it up and running.

Ok there are no leaks and I checked everything. Ran it till I needed to totally fill up the radiator after the stat opened up. The temperature was running the same as it did recently with my old radiator. It went up to 160 then the stat opened up and the temperature went down to about 150 then got up to 180 and stayed there and then want to kind of creep up to 190 and almost 200. It goes kind of back and forth and I get nervous with it doing that. I have no air bubble that I know of. But I don't want it too run 200. It always ran at 180 and stayed steady last summer.

Thermostat is a high flow non restrictive for high volume water pump. I don't have a shroud on it yet. I am going to have my dad custome make one from some sheet metal. Any advice.

Let me start by saying there is no such thing as a high flow thermostat, this advertising baloney. The purpose of a thermostat is to provide a flow restriction which is used to maintain a proper operating temperature.

Let me back that up with the statement that high flow water pumps are unnecessary. The fact that a stock engine comes with a thermostat and the function of a thermostat is to restrict coolant flow is evidence that a stock water pump already delivers more coolant flow than the engine needs. In fact the problem with high speed engines is getting the upper end flow reduced.

Now the problem you're seeing, the engine just keeps getting hotter, is classic insufficient radiator heat transfer capability. I've built a lot of V8 S-10/15 trucks and have yet to find a satisfactory aluminum radiator after nearly 2 decades of this activity. My own personal ride is one of these, so I have long term understanding of this beast. For my truck after a running many configurations, I settled on a 70's era Malibu 3 core radiator with an engine driven fan and a home fabricated shorty shroud. The shroud covers all edges of the radiator but is shallow because I run a long pump so there isn't much clearance between the fan and the core. I use a 180 thermostat which results in the engine running 190 in winter's near to sub freezing temps. In summer it runs about 195 on 100 -120 degree days pulling up mountain grades on the desert side of the state. So this configuration keep the engine temps well controlled. The radiator and fan combination is the result of having been thru dual electric fans, with and without an engine driven fan combined with Griffin, BeCool and Corvette aluminum radiators. None of this proved satisfactory. In the end the Malibu 3 core brass and copper does a better and more consistent job and will do it with the simplest fan solution. The radiator sets in factory bottom mounts. The top is bolted to the truck's upper radiator frame with a pair of factory rubber isolators sandwiched between the radiator's frame and the truck's radiator frame, retained with a pair of 1/4 inch stainless bolts and Nyloc nuts, with spherical washers to even out the loads because the bolts reside at a small angle between these frames. Aside from drilling a total of 4 holes no other mods are required to the truck or radiator.

Knock on wood, this set up is creeping up on the 100,000 mile mark and continues to provide top notch service using 100% Prestone coolant.

Bogie

[DENCOUCH]

A/C work is part of my job. Ya, A/c units come with fans to cool the outside condenser coils, & the fans have shrouds as well.

I like to think of them as dividers! The divide the air from one side of the fan from the other side. One of the cool things we show the new guys is how much the pressure increases if you happen to lay something next to the condenser coils and block the air flow.

It has the effect of reducing the area of the coil & the temps & pressures go up.

The same thing happens if a tech installs a new outdoor fan motor and does not mount the fan at the proper height in the shroud.

You need the air pulled through the radiator, guy. Get that shroud.