See if anyone can make heads or tales of this?

Harndog

New Member
May 28, 2007
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I to have a new motor like a few others on the board that likes to run around 230. it has never boiled over with just a 13lbs cap? However on the highway it hits 230 and creeps a little. As soon as I come to a stop hit the breaks the temp needle will drop to 190 maybe 200. I know this is not possible to just drop in temps like this so I am pretty sure gauge is the fault here. However the electric spal fan has a 180 thermo and it kicks in when the temp gauge reaches 190.

It's just a little un-nerving driving the car and seeing the gauge at 230 not sure why:shrug::shrug:

Anyway could the placement of the electric probe be the issue on the gauge? It is at the back of the Wieand stealth on the driver side.
 
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My 1993 Saturn SC2 does the same thing on hotter days. Highway cruising with full wind pushing into the nose of the car, the temp goes up near the redline ( rpm is up to 3000). Come to a stop, like at a light, and the temp drops back down to normal (rpm drops less than 2000). I've come to the conclusion the radiator doesn't get any outside airflow, and the electric fan can't keep up when it is above 60 degrees F. That would indicate a lack of cfm pull from the fan. May want to re-calculate how much cfm you need for your engine. Just a guess.
 
I to have a new motor like a few others on the board that likes to run around 230. it has never boiled over with just a 13lbs cap? However on the highway it hits 230 and creeps a little. As soon as I come to a stop hit the breaks the temp needle will drop to 190 maybe 200. I know this is not possible to just drop in temps like this so I am pretty sure gauge is the fault here. However the electric spal fan has a 180 thermo and it kicks in when the temp gauge reaches 190.

It's just a little un-nerving driving the car and seeing the gauge at 230 not sure why:shrug::shrug:

Anyway could the placement of the electric probe be the issue on the gauge? It is at the back of the Wieand stealth on the driver side.

Its possible the guage is messed up but I doubt it, I USED to have that problem to, and it turned out it was the guage. I think your problem is in your tune. It might be running a too lean when its in cruise mode, also whats your timing set at?
 
Not 100% on the timing my friend that has his own shop set it at 10% if I remember correctly the carb is a holley 600 4160 vacum sec. I do have a pro billet mechanical advance msd dist. The car seems to run really good. I do have a frame canister fuel filter and a stone inline??? not sure this is not overkill?? This is not a real hot build though the heads are ported rather well and are stock 65 iron heads. the cam is like 512 and 245 or something close lunati. I do have underdrive crank pulley ( because thats what summit sent I ordered the stock but figured what the hey) but the kit is suppose to have the oversized water pump pulley. with a milidon waterpump. My biggest problem may be the rad. I have a 65/66 northern with a Spal electric fan. I script here and made bracket for this to fit the 67 but my thinking was it's a mild small block 302 and lots of guys run them in the 66 and 65 cars so it should work. Plus it was cheap from a friend. Got the Electric fan from Mustang Plus Both are brand new.
 
Two things: get some stock pulleys on it and check the coolant level. Low coolant will give you erratic readings too. The small crank and large waterpump pulley is giving you an underdriven waterpump. Good for high rpm, but not good for a street vehicle.
 
Your problem is not your fan or your radiator, I run an Aluminum 65/66 radiator with a manually switched fan so that if I am cruising over 50 mph I will turn off the fan. There is more then enough air coming through the radiator at cruising speeds to keep our cars cool.
 
Make sure there is a spring in your lower hose too

My water pump was sucking my bottom hose together at higher rpm`s till I put the spring in it, acted the same way as yours, sort of.....