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Old 06-08-2023, 07:36 AM   #1
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Join Date: Apr 2021
Location: Lansing, MI
Posts: 353
Radiator fans testing and engine temperature gauge

2003, base, MT.

I noticed that, at least on the driver side, the fan does not activate on low speed.

Do they have separate relays? Low and High speed? And then separate for Left and Right? 4 relays total?? Any way to test them without Durametric?

Furthermore, if low speed is dead, is it the power supply or the fan itself?

Now, the engine temp.
I was told, 2 years ago, that the water pump was replaced. Sounds about right as I had to burp the system a couple of times. Not much, but noticeable. Now the coolant is steady.

It takes a while for the engine to reach 180 F. I get it, large engine (volume wise), plenty of coolant. Although still too long for my liking....
But then, when driving normally, it stays at 180 or so. On colder days slightly below 180 F mark, on warmer a tad above.

If I push it a couple of times and I reach say 200 region (halfway between the 180 mark and the next one), it will stay there. I do not see much of "down" movement, back to 180 or so, even after a longer steady drive.

What is the normal temp?
Can it fluctuate, in a sense visibly on the gauge, when driving?

My thinking - could the coolant flow be restricted? Could the thermostat be faulty - a tad open on cold - hence long warmup, and not opening wide enough on hot - hence keeping the higher temp longer?

The radiators are clean as I cleaned them last year. Added a mesh to avoid leaves accumulation for future. Mesh opening is about 12 mm square, so not so restrictive.

Current rides: 2003 Porsche Boxster MT (me), 2019 Bolt LT (me), 2015 Audi Q5 (wife), 2008 VW Rabbit (2.5 inline 5, MT, well, for kid... but you now, it is the 5 straight)

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