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I have found that my setup is does something similar, except the spike only happens on the prosport, while the cobb reads fine, then as if some magic happens it comes into line. I think my problem is the location of the pro-sport sensor being somewhere in lines with the heatercore and turbo. . . . most other times it reads the same.
Mine does something similar to what you describe as well, but I'm excluding that from my symptoms as I believe I know the cause there (at least for mine). My Prosport sensor is in the return to the radiator. While the t-stat is closed the sensor warms up while the coolant there is not moving. The wastegate and DP are also right there and add to the heat. The stock sensor still has coolant flowing over it. Then the t-stat opens and the Prosport temp drops and comes in line with the stock.
The part that I'm getting concerned about is when both are reading the same elevated temp.
Last edited by slash128; Mar 31, 2015 at 05:32 PM.
For example ambient temps have been mid 50's lately. I'll be cruising at a steady speed on the highway, flat, no hills. Coolant temp will be steady around 175-180. Then randomly it will slowly steadily rise to 195 and stay there, then suddenly drop back down to 175-180. I verify the AP reads the same behavior as the Prosport. My coolant level hasn't changed since I flushed it a couple thousand miles after the last motor swap last August so I don't suspect a leak. The coolant looked crystal clean when I flushed it so I'm probably just paranoid about the excess sealant after reading other threads on the issue. I know these are rather cool temps but it's the anomylous behavior that has me concerned.
Ya I'm not so worried about 195 in general. Im concerned about at 15-20 degree spike with ambient temps in the 50's. I'm worried about how high it will climb once we get into the 90-100 ambient temps...
So this morning ambient temp was 38F. As I drove flat city streets (30mph, not loading the engine at all) my coolant temps stayed in the 175 realm. I stopped at a light and the temp rose to 189 just sitting there waiting for the light to change (both the gauge and AP). While 189 is nothing to worry about that strikes me as a significant rise for the ambient being 38F. With the low temp t-stat I am used to seeing coolant temps hover in the 169-175 range when idling in cold weather. After a few minutes driving the temp came back down. If it were a stuck t-stat I would expect a temp delta between the gauges based on where the prosport sensor is in the rad return pipe, but they stay the same during this behavior, within a degree or two. It did this at a few lights. At the light I rolled the window down and I could hear the fans running high speed. The fact that this also happens at highway speeds leads me away from fans, as they aren't set to operate at those vehicle speeds.
Well at a stop temps will rise due to no flow across the radiator and oil coolers and why do you have your fans coming at that low of a temp? I have never seen the point of a low temp tstat, seems unnecessary to me.
I set the fans lower for testing. I realize there will be a small transient rise while stationary but 14F rise with ambient 38F strikes me as excessive.
just because the fans come on it doesn't mean they are operating properly
Yes, and temps will be low with airflow traveling at speed vs stopping as 9k stated. I don't see anything wrong there, looks normal to me.
If this is what the whole thing is about then you can always consider installing a better fan/shroud setup. A good aftermarket fan kit can pump out 3000 - 4000 cfm at 0 back-pressure rating, which is a whole lot more than the OE fans. I also don't really care for the OE fan strategy and would refer something like the Derale PWM controller. It varies fan speed entirely based on temperature. So the fans only run as much as they need to when they need to rather than cycling on/off all the time with fixed speeds. It bypasses the factory fan control and wires directly to the battery.
Assuming you have the OE S1 radiator, the core dimensions are 25.5" wide by 14.13" high
Ok, maybe I'm just so used to seeing lower temps during the winter months and I'm getting worked up for nothing as it's been warming up I'll keep an eye on things as we get warmer still.
Appreciate the info on the alternate fan solution. I'll be looking into that.
Slash, temps rise significantly when you stop both with the oil and coolant. For me, I have the FAL 420 (2500CFM) low profile setup and it works great, you can also get it with a nice fan controller (which I have yet to install). The FAL setup I have was by far the best cooling mod I have done, after a hard run they drop temps really quick, even so you are better off just stopping and letting the fans do their work rather than driving around slow to cool off. FAL also offers the 480 which is a 3000CFM unit and while not as low profile, it fits just fine, Hoss-05 has that setup on his Ron Davis rad.
Cool. I can understand while stopped, just seemed more significant than I recall past behavior. It's been winter too long Still scratching my head about the rise while steady state highway cruising. I'll keep an eye on things.
It's official. I'm done with with stupid rotary engine. It guzzles fuel and oil. I bought this car because I wanted good MPG, eco friendly and room for my wife and 4 kids. This car is a joke. If i wasn't broke I'd buy something else but an LS1 swap is so cheap and easy so I'm going that route instead. I'm picking up a stick welder from HF today. Rotaries suck and anyone who likes them is a loser. Anyone know if I can use the stock PCM with an LS1? I mean I know it has twice as many spark plugs. I was thinking I could run an extra set in parallel when I want POWA and then have them shut off for fuel economy. Thoughts?
Ooh just thought a 4 position toggle switch with the 4 extra spark plug high voltage leads wired to it in the cabin would do the trick. No messy controller, just beast mode/eco mode at the flick of a switch!
Got tired of trying this come up with ways to keep my MAF dry so I did some experimenting and was able to get it back in the engine bay. Eliminated the piping out front. Filter fits straight forward into the bumper recess. So far so good. No erratic MAF readings yet...
Huh... I got my maf out of the engine bay (and away from the turbo) to keep it dry.
In all seriousness though, I put a deflector plate above my air filter to prevent rain from causing serious issued. Without it I can't drive in the rain.
I have had my filter in that exact spot from day 1 . You will still need to deflect water off it that will location . I just ran a bead of silicone along that steel bracket so water tracked to just beside the filter . The plastic cover fits over top of that.
Huh... I got my maf out of the engine bay (and away from the turbo) to keep it dry.
In all seriousness though, I put a deflector plate above my air filter to prevent rain from causing serious issued. Without it I can't drive in the rain.
Out the bay to keep it dry? Interesting, how come? I've not had water in the bay. I was using ziploc baggies and had a deflator piece of plastic at one point. It all worked but needed constant attention.
