So I finally bought a laser temp gauge today while I was running around for a couple hours. With A/C "on" the entire time my temp gauge ((not that its accurate) went up as high as one needle width past the 210*F mark. For my engine...thats FRIGGIN HOT. My temp gauge usually never gets near the 210*F mark. Today was a ton of stop and go driving and its damn hot today. When I saw it getting really hot, or what I think is hot, I pulled into a Harbor Freight and bought a laser temp gauge.

So....really, my 1998 temp gauge is pretty accurate for coolant readings...within less than 10*F.

Power Steering Fluid temps (*F): leaving the exit port on my aftermarket cooler.....111.4*F The entry port read 125*F. ((I couldn't get under to hit the lines coming out of the rack....the damn cement I was kneeling down on was 146*F......))

Coolant temps (*F): Drivers side head was 206*F. I hit the brass part of the temp sensor 208*F. I hit the lower rubber radiator hose and t-stat housing, both were 188*F. And then the brass part of my crossover hose fitting from the head 211*F.

Damn dashboard was 120*F......
A/C air coming out of my vents after moving steady at 45mph.....41*F

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Those are pretty much the p/s temps I was getting after a spirited drive in warm weather. Not quite the heat you are talking about! Def cooler than the coolant temps our cars run at!

 

I was surprised the PS fluid cooler was so cool...especially how crazy hot is was today. Maybe that cut out in my air dam really makes that much of a difference. I'd like someone to get readings who has their cooler mounted behind the air dam with out the cut out.

I was also surprised how accurate my temp gauge is for my coolant temps.

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No cutout for mine - yet. Did you ever take the temp of the p/s dipstick/cap? I got my hottest temps there, maybe 10-20*C higher than the exit of the cooler. After spirited driving around town, highway blasts etc the temp of the dipstick was 55-60*C, around 130-140*F at the *highest*.

 

Tomorrow its gonna be just as hot as it was today......I'll do the dipstick and cap....as well as the metal high pressure line coming out of the reservoir.....that metal line should be the hottest of the entire system.

I'll be putting in my 180*F t-stat too.........I'm almost certain its sticking....or opening very slowly, but shutting quickly. Now that I know how accurate my coolant temp gauge is at high temps, I'll pull over when I see it hit the 155*F mark to see the low temp accuracy.

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Sounds like your thermostat is sticking.

Looking forward to the reservoir measurement. That will be a direct measure of the fluid temp. (I had a similar experience when lasing my cooler. The cooler temperatures were far less than the fluid.) Kind of makes sense since the outside of the cooler is where the "cooling" happens. I'd expect if you let it sit for a while, the fluid will warm up the cooler more if air hasn't been running over it - and it will essentially turn in to a radiator.

 

Yup....I put the 180*F t-stat in and its running nice and cool now, holding my temp more steady. AND...its better than the 160*F because now what I think is happening.....when the coolant gets up to 180*F and the t-stat starts to open and dumps all the hot coolant, then closes. The coolant has more time in the radiator to sit and cool down before it opens again...unlike my 160*F that would open 20*F sooner.......
It seems that way.....but its only been one day. I'll keep watching it and see what it does....BUT ITS VERY NICE NOW.

I was just busy all day to pull over and hit the PS fluid reservoir with the temp gun. I'll try to do it tonight on my way home from the gym....if not I'll definitely do it tomorrow in the middle of the day when its real hot. I'll hit the high pressure line coming out of the reservoir...and I'll also get a reading of the fluid itself by taking the cap off while its hot. I've taken it off many times when its hot.

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From what I've read, your assessment of the car running cooler with a 180 vs 160 'stat is correct. At least now the fluid will sit in the rad a little longer and dissipate some heat. Some guys wonder why running no 'stat at all would allow the car to overheat but it makes sense about holding the coolant back to be cooled. It's getting cool here so my p/s temp readings wont be a good indicator of anything at this point.

 

With no thermostat, the bypass port in the pump housing is always open, this allows the pump to directly pull in the hot coolant that is exiting the block and push it back into the block (i.e. the path thru the block has less resistance compared to the path thru the radiator, so most of the coolant circulates in the block only, and very little goes out to the radiator)... this is why it overheats with no TS.

When the TS opens it blocks the bypass port (the open TS increases spring pressure on the bypass port valve), this causes the hot coolant exiting the block to go out to the radiator, and the pump pulls the coolant in from the radiator via the open TS.

 

LS6427,

Those laser temperature guns are very handy, there are many things to point at...

Your air dam slot looks like it is working very well...

 

Yea, the slot must be working quite well.....my cooler is always just warm to the touch.

I did find though, about the laser gun I bought.....if I hold it say 14 inches from something it will give a very different reading than if I hold the gauge right up 1 inch away.

For example......14" from my brake rotor was like 145*F....right up almost touching it was 225*F.

The directions don't say how far to keep it away from an item.......

So I'm wondering if any of these laser pointer temp gauges really work UNLESS your are actually 1 inch away from the surface being checked. Because that big variance in temperature on different surfaces works on everything. Right now.....14 inches from my air conditioning vent in my bedroom reads 59.1*F....right up to it reads 52*F...BIG difference when accuracy is needed.

14" from the lightbulb in my lamp....105*F.....1 inch away from it...268*F

14 inches from my bottle of water...81*F.....1 inch away......76*F

****Oh, and my $12.99 Harbor Freight temp gauge shows the same exact readings as my stepfathers $350.00 laser temp gauge....

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If you paid less than $60 for it, it won't be very accurate. Better models tell you in the instructions how far to hold it away. All sensors have a "cone" that they measure the temperature across. The farther you are away, the larger the circle of area being measured at the end of the cone.

In order to measure temp from a distance, you'll need a model that measures a narrow beam. Nicer devices have a laser pointer integrated so you can see which area you are shooting at.

 

Mine has the laser pointer which def makes it easy to determine what you're reading...

 

Some models have two laser pointers... at the correct distance the laser dots coincide.

Also, the temperature read depends on the surface/finish of the object... shiny metallic objects give different readings than flat black objects even tho both are in contact with each other.

 

Now ^ this is interesting. I did notice that when I took the temp of the fluid in the reservoir, it may be different from the reading of the black dipstick/cap assembly, even though the dipstick is in a bath of the p/s fluid...

 

Yeah reflective vs non reflective will give a much different reading. I think it actually might say that in the directions somewhere. When I was setting my electric fan temp on my jeep I used a piece of black tape on the top of my radiator to get a nice non reflective surface. The closer you can get to an object the better reading it will produce as well. The gun does not measure in a straight line, rather a conical shape from the point of the gun. So the farther away you are from an object the more other objects you will catch in the cone. When the temps are averaged together to get a reading it can be really far off. Check out page 4 on this link for a diagram:

http://manuals.harborfreight.com/man...6999/96451.pdf

 

Like I mentioned........my cheap one reads the same temps as my stepfathers $350 gun. But mine has to be 1 inch from the surface for it to be accurate. I tested them at his plant where he's an engineer on surfaces that the temps are known for sure. I'm surprised that this little cheapo is accurate up to 380*F....its exact right to the degree.

I'll get some readings of the PS fluid tomorrow..........

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Yes, you'll be (are) surprized...

same goes for the cheap electronic vernier calipers.