Hills and temperature

[ZachFD]

I might just be nuts, but it seems like my water temp always reads higher when I'm on an incline than on a decline....not necessarily under a climb, even when sitting still.

I was cruising on the interstate in 100F temps the other day at 70mph, my fans were on and my temp was around 195F. All was fine until I hit a slight incline on the interstate...temps started creeping up to 215F so I turned the heat on...dear god my skin roasted but temps dropped back to 200F. As soon as the slight incline was over, temps dropped immediately back to 195f.

Car NEVER used to do this with fans on when I had it all stock. It would sit at 185F all day long. My only mods are SMIC/Large Aluminum Duct for I/C, Aluminum intake pipes, Airpump delete, DP, Koyo radiator. Could all the aluminum cause heatsoaking?

Same thing happens on hill when I am sitting, like at a light on a hill with fans on...my temp will climb from 185F and start climbing until I face downward.

Does this sound like a slipping waterpump/poor circulation...maybe on an incline, gravity is pushing the water to the back of the radiator/motor and pump can't keep up? I do have the stock wp pulley w/ airpump removed. If I try to turn it, I can with my hand, but the belt still gets enough grip to rotate. I have a larger pulley ready to put on.

[ZachFD]

come on guys

[Signal 2]

Possible. But I personally have never heard of this before. Is it possible that going up hill your simply loading the engine and/or loosing some head-wind you had on level ground? And 215 F. is not unheard of with a triple digit ambient temps and high engine load.
Running your car with the stock WP pulley and no airpump isn't a good idea, but unless there's evidence of severe slippage...worn/shiny belt face and noise, it's probably not soley responsible either. In my experience, slippage is usually during cold start, quick acceleration and high rpm. Since you mentioned you recently added those mods from stock, other things that might have influenced the change.....
*Your coolant to water ratios were changed?
*Some air was left in the system?
*Did you fill the gaps around your radiator with foam?
*Your belly-pan isn't completely secure?
*Making sure your relays are working properly, the connectors are secure and fans are coming on as they should?

On a side note you could also consider....
*Install of an FC (IIRC 89 to 91) thermoswitch to lower threshold temp for fans to come on
*Adding the airpump idler pulley to keep full belt contact (Garfinkle and Chadwick both sell them here as authorized vendors)
*Redline Water Wetter

[Garfinkles Motor Works]

Let me sell you an Idler that goes where the air pump was that may help .Look in the vender section under Garfinkles motor works ,also look at Dan Chadwicks sight for an other design,different from mine .Both work fine just different . Is your water level full for sure .

[ZachFD]

water level is full, no air in the system. Never have the buzzer go off. Neck is always full when I pop the cap off cold.

*No slipping on start up or squealing.

*I have a larger WP pulley I'm about to install.

*I have a fan switch wired to one of the relays that was on the car form the previous owner. I'm guessing it keep the fans on medium or low...not sure which one. If I flip the A/C switch with the car off but ignition on, fans speed up.

*Undercover is cracked towards the back in places, but the front half from the oil pan foward is pretty sealed up. I do have foam around the radiator gaps.

*I have the AST relocated to the side of the engine bay...its bolted where my battery used to be...battery is relocated.

*I have Large SMIC with Aluminum Ducting. I'm thinking either this is causing heatsoak, or my fans just aren't running fast enough with my fan switch to cool down the car. I"m too afraid to run it up to 225 to let the stock fan sensor kick in.

*If I turn the heat on, temps always drop DRAMATICALLY (which is why this is puzzling).

*Also, I CANNOT, CANNOT, run the a/c in this heat...even on the interstate, at 70mph, the car will creep really fast in temps.

*I also have dual oil cooler....my temp sensor is the Defi D-gauge and I believe the sensor is tapped at the water pump.

*When I first purchased car, before the I/C/Duct/Airpump removal, the car never creeped above 185 with fan switch on.

*I've checked the thermostat, replaced it twice. I've changed the coolant probably 4 times in the past 3 years. 80% water/20% Coolant


Please help me figure this out....I just want to know whats causing the creeping temps before I purchase anything...whether it be the aluminum intercooler duct blocking airflow from the fans, fans running too slow, or undercover being cracked. In the winter car stays pegged at 180F

[Signal 2]

I've never heard of "aluminum ducting" for a SMIC, how much are you taking away from the airflow to the radiator? At any rate, "heat soak" shouldn't be an issue when your moving.
Consider that FC thermoswitch, it will lower threshold for the fans to come on from something like 108 C to 95 C. (226 F. to 203 F.) and is simple replacement...no modifications.

[ZachFD]

you've never heard of it, because it was custom fabbed. Problem is I'm worried it retains to much heat and maybe thats the issue? I guess Ill try taking it out to see if temps drop. It doesn't block to much flow in the bumper tho.

[albertomg]

Sounds like you have some air in the system, a bad thermostat and/or coolant that is no longer working properly.

i'd also like to see some pics of your setup.

[Signal 2]

Your temps of around 215 F. really don't seem out of line for a 100 degree day IMO. Would I keep an eye on it? Absolutely. You always should anyway, but especially on a hot summer day. And I'd try to stay out of boost as much as practical too. But as mentioned above, the stock thermosensor doesn't even trip fans until 108 C. (226 F.).
BTW, while turning the heat on will help a little, it's probably the electrical draw of the heater fan turning on the radiator fans that was doing the most good. Just think, with the FC thermoswitch, you wouldn't have to do that anymore.

[ZachFD]

Originally Posted by Signal 2

Your temps of around 215 F. really don't seem out of line for a 100 degree day IMO. Would I keep an eye on it? Absolutely. You always should anyway, but especially on a hot summer day. And I'd try to stay out of boost as much as practical too. But as mentioned above, the stock thermosensor doesn't even trip fans until 108 C. (226 F.).
BTW, while turning the heat on will help a little, it's probably the electrical draw of the heater fan turning on the radiator fans that was doing the most good. Just think, with the FC thermoswitch, you wouldn't have to do that anymore.

You must have missed that i have a fan switch wired to the relay system. Fans are ON when I want them to be on....car creeps to 215 with fans ON. Maybe they just aren't running as fast with my switch as they would with a thermoswitch.

I don't think there is air in the system because I remove the cap after the car sits for a while and theres no release of pressure or gap of air.

[Signal 2]

I did forget you mentioned that switch. Is it possible it's bypassing the high speed fan relays and your just stuck on a lower speed?
In my experience typically (but not always) if there is air in the system, you'll hear that boiling sound after shut down. And while the car is running you see spiking of temps...not so much a steady rise as you've described.
I also don't see how heatsoaking of the aluminum IC ducting could have anything to do with it.

But I can't think of anything else to suggest. Sorry.

[ZachFD]

Originally Posted by Signal 2

I did forget you mentioned that switch. Is it possible it's bypassing the high speed fan relays and your just stuck on a lower speed?
In my experience typically (but not always) if there is air in the system, you'll hear that boiling sound after shut down. And while the car is running you see spiking of temps...not so much a steady rise as you've described.
I also don't see how heatsoaking of the aluminum IC ducting could have anything to do with it.

But I can't think of anything else to suggest. Sorry.

hmm, after shutdown I do hear a bubbling sound that comes in groups.....ill shut the car off and after a minute or two ill hear brsh,bhrsp,bhrsp.........brsh,bhrsh, I thought it was water returning into the system from the overfill due to heat expansion/cooling

My buzzer never goes off, and my level is always full at the fill neck, so i figured theres no air in the system...however, is the AST supposed to be at a high point above the filler neck, because mine isn't

[rx4ur7]

You still have air in the cooling system.

Heat soak is an issue when you shut down. As long as air is flowing you are getting some cooling effect. Polished aluminum will not exchange heat as well as non polished. Steel and iron are going rise more and hold the most heat on a soak.

Lack of good air flow through the engine compartment will also cause temps to rise. But that would show in all conditions and get worse the faster you go.

A blocked or partially blocked exhaust will cause temps water and oil (when extreme) to climb on a incline. Leaking housing seal will also cause it. A FC3S just came in that got hot going up Mount Lemmon. Temps went up on the way up but were fine on the way down. When I checked it it is now pushing water.

From your discription of the gurgling I would do a bubble check, just to rule it out a seal issue.

Easy enough to do the bubble check for seals,
Start it up cold with the fill cap off.
It will push a little coolant out as it expands but once it comes to temp it will stabilize.
Let it get to full warm up.

If a seal is going - These guys will start with very fine bubbles, so small they can look more like dust. And there may only be one or two in 10 or 15 ses.
The next stage is there are enough that they form a foam.
Next bigger bubbles, becoming large enough that when they break you see combustion gas.
Last stage, blows water out as soon as you start it.
In the very early stages there will be no signs until it reaches full operating temps.

General Rule of thumb, You can be allowed 3 overheats (close to the mark) before $$$$.

[ZachFD]

Originally Posted by rx4ur7

You still have air in the cooling system.

Heat soak is an issue when you shut down. As long as air is flowing you are getting some cooling effect. Polished aluminum will not exchange heat as well as non polished. Steel and iron are going rise more and hold the most heat on a soak.

Lack of good air flow through the engine compartment will also cause temps to rise. But that would show in all conditions and get worse the faster you go.

A blocked or partially blocked exhaust will cause temps water and oil (when extreme) to climb on a incline. Leaking housing seal will also cause it. A FC3S just came in that got hot going up Mount Lemmon. Temps went up on the way up but were fine on the way down. When I checked it it is now pushing water.

From your discription of the gurgling I would do a bubble check, just to rule it out a seal issue.

Easy enough to do the bubble check for seals,
Start it up cold with the fill cap off.
It will push a little coolant out as it expands but once it comes to temp it will stabilize.
Let it get to full warm up.

If a seal is going - These guys will start with very fine bubbles, so small they can look more like dust. And there may only be one or two in 10 or 15 ses.
The next stage is there are enough that they form a foam.
Next bigger bubbles, becoming large enough that when they break you see combustion gas.
Last stage, blows water out as soon as you start it.
In the very early stages there will be no signs until it reaches full operating temps.

General Rule of thumb, You can be allowed 3 overheats (close to the mark) before $$$$.

well the temps always drop when I'm moving...it just heatsoaks really bad at idle with fans on...the fans just dont seem to keep the temps down.

The gurgling occurs when the car is shut off....it sounds like water returning into the overflow tank slowly from the vaccuum.

As far as the fill neck, I get very very very very tiny bubbles in the neck. They don't occur at cold start...they occur as the water level starts to rise as the car is warming up. Very little bubbles that do look like dust but its not a steady stream and they don't look like they would cause pressurizing. They do not speed up as the engine is revved I don't think....

---It really seems to me like these bubbles are just from the movement of the water pump.

Should I just do a hydrocarbon test? Wouldn't this tell me if those bubbles are exhaust gases? BTW I never have overflow issues or loose coolant from the fill neck.

[Doc-1]

My 2 cents. You have air in your system. Would explain it.