High Engine Temps

[troonman60]

I have a 70 chevy with a 454 and currently have been noticing that my temp seems to be getting pretty high. (230 degree range and higher going uphill) After searching this site it is i read it is recommended to have your cooling fan half way out of fan shroud for max air pull. Upon further investigation I noticed that my fan is completly inside the fan shroud, fan shroud is in rough shape and has a big air gaps on the top. Could this be causing causing my issues? What type of new fan shroud would be the best to use for 454 setup? Thanks in advance.

[dwcsr]

Unless that hole and fan depth was recent along with the high temps then its not your issue. Are you using any water? Any white vapor out the pipe?

[Sammy]

I agree even in Az you shouldn't be running into high temps in Jan. Might check thermostat, or head gasket or something else. If you still suspect the fan though why not get a custom shroud and a pair of electric fans should keep it plenty cool even in the Az summer 100 degree plus summer.

[cdowns]

have you checked the actual coolant temp with a know good thermometer?
gayges and sending units go bad

[bikertim]

Had the same problem with a truck long time ago -- the clutch fan was shot so the fan wasn't pulling through enough air. Changed and never had another problem.

Has big gap in shroud always been there? Shroud is definetly needed to keep a BB cool in AZ. I tried a single electric fan a few years ago and it wouldn't keep my 70 chevy with 454 cool in traffic with AZ on, stock set up does. Check thermostat like someone else said too!


Good luck!

[Longhorn Man]

Does it heat up when driving at low speeds... 40 MPH and less, or is it when you are going faster?
Generally low speed overheats are air flow problems, and high speed is coolant flow problems.

[ripdog28]

Up hill (Against the wind and with a trailer) is not a problem. It you only travel up hill then i guess it would be. but if it ony happens because of that then i do not see any problem. If it happens with normal driving then you have a problem. Any who, check the gauge and replace the thermostat ($5) if still, fix the fan.

[67ChevyRedneck]

What size radiator do you have?

Big block trucks came with a 4 row radiator and a big ass 7 blade clutch fan, so I would think a 454 would need the same. If you have an automatic, a trans cooler will help a little too.

[DZL1]

Your tstat might be stuck. Try replacing that and see what happens. Similar thing happened to my truck. Changed tstat, fixed problem.

DZL1.

[troonman60]

Thanks for all the replies, It only seems to get hot when going at slower speeds or under load (going uphill). I also forgot to mention that I have replaced the thermostat, radiator cap and fan clutch. (all the easy stuff I could think of). The water pump seems to working fine. This is why I am wondering what effect the gap in fan shroud and fan sitting to far into shroud could be causing this issue as well.

[Sammy]

I have heard of folks boring blocks to the point of them not cooling properly. One reason why I personally frown on folks boring to the max for an extra few Hp. Might be that the water passages or even the engine work wasn't the best. Even some of the head machine work folks do are not as experanced as they claimed. Do you know the history on the engine. rebuilds etc?

[clay68c10]

Have you verified the temp with another gauge or an infrared temp gun? I'd say your fan situation isn't helping. Do you have a factory BBC shroud? What accessory drive do you have? These trucks came with short waterpump accessories, so the fan sits a few inches back from the radiator and at the edge of the shroud.
I have seen my 454 get up there when I lived in TX; summertime with the a/c on it would get over 210 stopped, but would stay around 205 at highway speeds. After an engine off 10min heatsoak it would be close to 230 at startup, but would drop immediately after startup. It seems to be happy at these temps, but I'd say you're running a bit high.

[troonman60]

I bought the truck about a year ago so I don't know the history of the motor. I believe I have a long water pump, the fan clutch is pretty close to the radiator. As far as factory BBC shroud I am not sure. The one currently in the truck is in rough shape maybe worth while to get one. Where can you get a factory BBC shroud and do the need to me modified for 1970.

[ryanbenn1207]

I just have too ask cause it happened to me lol make sure the fan was bolted on the right direction if you dont know the history of the engine

[Hatdcorechevynut67]

Sounds like a perfect candidate for a dual electric fan setup. Replace the temp sensor and Have the radiator pressure checked and Flushed by a pro.

Sometimes when they haven't been maintained well they will get blocked passages and it will cause higher temps because the water flows through too quickly. Just my personal experience talking but it may help. a good radiator shop can flush/boil and pressure check a radiator fairly cheaply. I think the last one i had done was around $40.00 Good luck and let us know if you figure out what was causing it.. A.J.