Coolant Temp Creep
 

Well, temperatures in VA have risen above 80 now here in VA. I noticed the other day that the coolant temp has risen as well. I normally run a needle width above 1/4 on the gauge, but now it's been creeping a little over half on the gauge. I tried searching, but to no avail, I found nothing. I've got a SP 12a with RB exhaust and Holley setups. E-fan from a Volvo 850 Turbo. Only thing is, this creep is occuring at 65-70 MPH. I figured at these speeds, the amount of air going through the radiator would be more than sufficient. I expected an increase, but not this much. I'm thinking the t-stat might be sticking somewhat closed, but open enough to not overheat. What are your ideas? I'll be putting a new t-stat in tomorrow, but would like other suggestions.

Thanks,

Bryan

check radiator flow. perhaps a flush is in order? also, verify that your thermostat is a 180 degree and working properly. while you're in there, check your belts as well.

double post

Is your fan on all the time? If it is, it is blocking the air flow through the radiator. At highway speeds the fan needs to be off and freewheeling.

If the fan is on constantly, add a thermo switch in the circuit.

if your fan is on and temp continues to increase at highway speed, then your radiator is clogged and needs a rod-out.

Well, got home tonight, and it seems to be getting worse. I haven't changed the t-stat yet, but will do this tomorrow. The fan is off at highway speeds. I will try to flush the rad, but I'm pretty sure wacky is right. I turned the heat on full blast (boy was that fun) and the temp lowered slightly to about 1/2 which is way hotter than it normally runs. Most likely I'll be buying a new rad. Belts are nice a tight. No unusual noise under the hood, and the coolant level full. No sweet smell in the passenger compartment. I pressure tested the system today, no leaks. I was surprised to see that when I popped the cap while it was hot (the cap was covered with 10 rags literally, and I had on protective stuff) that little to no pressure was to be seen. So, with those facts, Wacky almost has to be right. Off to find a Rad at a decent price.

Thanks for the help.

Wacky, I have to disagree with you on this one. :D

A fan that is powered a highway speeds can actually restrict the flow of air coming through the radiator, thereby causing the temp creep he is having. If he is experienceing no heat issues in low speed speed, stop and go traffic, then he needs to install a thermostat for the fan, so it shuts off and freewheels at normal operating temps and below.

I know this one from experience. :bigthumb:

Im not disagreeing with you at all as there other factors involved. But the common diagnosis is a clogged radiator.

I disagree with the agree who disagreed about the agreer agreeing with the disagreer who then told the agreer about disagreeing.

The fan restricts air flow at high way speeds, thats why the clutch fan is only used at low speeds.

- Tech

how much restriction can you get from the electric fan @ off position? maybe 5 degrees the most. Dont forget that it will spin also at freeway speed.

I normally have the fan off at highway speeds anyway. Just ordered one from Radiator.com, so it'll be here tuesday.

While I was typing my post, you posted this one, so now i have to agree with Wacky. :eek:

I will go have my piece of humble pie now. :D