Cooling issues

[five&dime]

My car heats up to the P when I am going about 80 or so. I don't have a fan shroud or a lower pan. Well I just got them and need to install this weekend along with my new alt

I may also change the thermostat out. Of course I don't remember which one I installed.

[DryHeat]

Just checked the lower radiator hose and it is not collapsing.

Byron ... thanks ... I just tested the water temp in the upper radiator hose and it is about 162 ... new gauge says 180 ... hmmmm .... guess I'll gt another one.

P.S. Nobody tell my better half that I used her candy thermometer.

[okayfine]

P.S. Nobody tell my better half that I used her candy thermometer.

Not to add to the issues, but you might want to calibrate the candy thermometer . I've had widely varying accuracy from them, and it's easy to test at 212°. Easier than finding out a batch of caramel will cool into a rock when only cooked to "soft crack" stage.

[Byron510]

P.S. Nobody tell my better half that I used her candy thermometer.

Not to add to the issues, but you might want to calibrate the candy thermometer . I've had widely varying accuracy from them, and it's easy to test at 212°. Easier than finding out a batch of caramel will cool into a rock when only cooked to "soft crack" stage.

You have any idea how many turkey basters my wife has "lost"?

Byron

(Yes, as okfine said - you can always stick the end of the gauge probe into a boiling pot of water - either taking the whole gauge into your kitchen, or break out the camp stove or electric plate - put it under the hood with the pot of water and hold the probe in place - depending on what is easier.)

((I just googled "baster" to see if I had the spelling right - and got this:
http://www.google.ca/imgres?imgurl=http ... 7&ct=image
I didn't know weather to stare or feel sorry for this young girl!
I apologize up front if I have just started a string of thread hijacks..))

[DryHeat]

Very frustrated.

I found another thermometer in a box of stuff my dad left me and checked the accuracy in a glass of ice water ... 34 degrees. Stuck it in the coolant temp and it measured 164 (same as the candy thermometer). Gauge still said 180 at idle again. Went a purchased a new AutoMeter guage and tested it in the coolant while the engine was running ... 167 degrees. So I figured that it was just the gauge(s) that were not working correctly.

Installed the new gauge and went for a spin ... at freeway speed temp climbed to 202 and was still creeping up as I shut it down and headed home on the surface streets ... the temp did drop to around 180 while I limped home.

So the harder I drive her the hotter she gets (insert a few snide remarks here).

Is it possible that with the spal electric fans that I am actually deflecting/blocking air flow at higher speeds and not allowing the radiator to cool efficiently? FYI these are pullers and they are spinning in the correct direction. I will probably yank the fans off this AM and stick the old mechanical fan back on as a test.

[okayfine]

So the harder I drive her the hotter she gets (insert a few snide remarks here).

Is it possible that with the spal electric fans that I am actually deflecting/blocking air flow at higher speeds and not allowing the radiator to cool efficiently? FYI these are pullers and they are spinning in the correct direction. I will probably yank the fans off this AM and stick the old mechanical fan back on as a test.

Can't imagine the fans are blocking enough air flow to alter cooling performance on the freeway.

What is the difference in RPM between your freeway jaunts where the temp creeps up versus your side-road return path where it runs a relatively normal temp? If there's a significant RPM difference, you might try side roads at the same relative RPM (maybe in a gear lower so you don't break too many speed limits) to test. If you're reving it out on the freeway and not on the side streets, it could be that there's some sort of restriction in your cooling circuit that prevents full coolant flow at that higher RPM.

But at least you go the gauge sorted

EDIT: Reread some of the Page 2 posts. Are you using the same radiator from before the 2L swap? Did you have it rodded out when the car was down? Seems like a common denominator between the old engine and the new one.

[DryHeat]

RPM difference is only about 1500 or so. When I'm on the freeway the engine hits around 3k and when crusing on the street it varies but 1500 - 1800 is about where I keep it.

I agree that the radiator seems to be the last common element ... while it was installed about 18 months ago it only has 100 miles of total driving on it. The Rabbit radiator I have has the plastic tanks so I don't know if a radiator shop can do too much to it. I have a stock dual core and a Fiero radiator sitting in the garage ... I keep tripping over the Fiero one so perhaps my 510 Guardian Angel is trying to tell me something.

[hang_510]

unless your checking the temp at the same spot as the indicator, there will be some variance, not 20* but some...

have you tried it w/o a thermostat to see where it gets too?
what about turning the heater on when it starts to climb?

ive seen more than 2 thermo's in a row be defective...

maybe time for a 3-core radiator...(its the dry heat dontcha know!)

I didn't know weather to stare or feel sorry for this young girl!
I apologize up front if I have just started a string of thread hijacks..

quit staring!
she looks like a master baster

[Byron510]

RPM difference is only about 1500 or so. When I'm on the freeway the engine hits around 3k and when crusing on the street it varies but 1500 - 1800 is about where I keep it.

I agree that the radiator seems to be the last common element ... while it was installed about 18 months ago it only has 100 miles of total driving on it. The Rabbit radiator I have has the plastic tanks so I don't know if a radiator shop can do too much to it. I have a stock dual core and a Fiero radiator sitting in the garage ... I keep tripping over the Fiero one so perhaps my 510 Guardian Angel is trying to tell me something.

I’m just going to throw this out there – what are your pulley sizes? (crank vs water pump).

You know, it’s possible that, with the age of our cars, and the interchangeability of everything, that you have a combination that is just way off – and are possible cavitating your pump, and therefore not circulating water at higher engine speeds –it’s unlikely, but just a thought.

And forgive me since this thread has been long – you are running a thermostat, right?

Byron

[DryHeat]

Byron ... the water pump pulley measures about 5.5 inches ... crank is a stock L series cast pulley ... and I am using a 165 degree thermostat ... which appears to be working fine.

I ordered some brass inserts for the rabbit radiator so I can attach a modifed fan shroud and once they arrive I will be putting the mechanical fan back on the motor. They should be here sometime tomorrow.

If this doesn't fix the issue then I will be installing the Fiero radiator ... as Okayfine pointed out it is the last common denominator.

Silly question though ... I am running a Weber 32/36 and the engine runs great with tons of power. If I were running too lean would that cause an abnormally high cylinder temperature and result in an inability to cool the engine. If so how can I check this out.

[defdes]

Too lean or too much advance (sorry, I haven't read the whole thread) will cause the higher temps. The best way to see if it's a lean condition is get the car up to running temp, take it up to 5th gear on a cruise, and cut the engine and coast to a stop. Then check your plugs.

[duke]

Too lean or too much advance (sorry, I haven't read the whole thread) will cause the higher temps.

I was under the belief that retarded timing could cause running hot. I had the mechanical advance stick on my l-series dizzy and it would get hot while cruising on the freeway. Turned out that I wasn't getting any more than 12 degrees of total advance.

[DryHeat]

I had the mechanical advance stick on my l-series dizzy and it would get hot while cruising on the freeway. Turned out that I wasn't getting any more than 12 degrees of total advance.

HMMMM ... that sounds really familiar ... I'm using the same distributor / ignition setup as I was before. Another common denominator and so I'm off to the garage to investigate. Thanks Duke.

Update - Initial timing @ 12 degrees @ 750 RPM ... 35 degrees of total advance at 3000 RPM.

[DryHeat]

Ripped the radiator out and found something I don't understand ... hoping someone can explain.

This is an aluminum Rabbit radiator with plastic tanks on each end. The "rods" in this radiator are nothing more that 1/4" (inside diameter) straight round tubes that are wide open on the end ... All the radiators I have ever seen use a "pinched" end. Granted I can only see one end of the tubes.

Based upon the high flow rate generated by the engine at higher RPM's ... How in the world can this radiator cool? I would think that the coolant would be squirting through there so fast that it wouldn't have enough time inside radiator to disipate much, if any, heat at all.

I'm sticking in my Fiero radiator and giving that a try ... the inside looks like a nornal setup to me.

[bertvorgon]

Called "resonance time", the time that the water is actually in the radiator, which is a function of how long the themostat stays SHUT. This is when the thermal transfer happens. My rad is NOT pinched on the ends, and has max flow when the water would move through. Not having the pinched ends lets a less restricted flow of water transfer from the rad to the block, quicker. I can watch my temp gauge actually fluctuate as the thermostat opens and closes. It gets less pronounced as the thermal load goes up, and it becomes quite stable on the gauge.

At higher RPM ( and load potentially), the thermostat just cycles faster, which is why we put the bigger radiators in, in the first place, to cool the mass of water, by having greater area. Only problem at high RPM becomes one of the water pump running beyond it's original design parameter, and cavitating. That becomes a problem. Most of us are ok as we never see SUSTAINED high rpm for any length of time. I run a larger pulley on my water pump, as my engine does see some sustained high rpm, with very high thermal load (boost). I run a Monza cross flow rad, and my water temp stays at 170 most of the time, with a 160 thermostat. I have more of a problem at LOW speed, as the pulley turns slower, and so when the thermo opens, it is not pumping much volume at low (idle revs).

So, our engines become a balance between a good size radiator, temperature of the thermostat, and the type of water pump you are using. I use the 280zx one, again for the higher volume, comensurate with the bigger radiator.