Radiator fans start on Low at 217F instead of 206F

[sasha055]

Hi,

We finally got a warmer weather in Seattle and I noticed that the car started running hotter then usually.

After a couple of tests I found that my DME does not start the fans at 206F it starts them at 217F

Here's the tests I did:

1. Radiator fans turn on when I start AC and both of them are working properly (napkin was stuck to the grille on both sides)

2. I started the car and waited for it to warm up and fans to start. I watching the temp on AC LCD.

Fans started when temp climbed up to 103C (217F), engine cooled off quickly and fans stopped when engine cooled to 99C (210)

3. I checked my relays, by putting finger on the and turn AC on/off. When I turn AC on, low speed fan relay (19 & 21) is clicking and fans start, so it's not a relay.

I also run the car on idle until fans kicked in automaticaly while keeping my finger on the relay. When coolant temp reaches 103C low speed relay klicks and fans start.

Why is my car starts fans at low speed at 217F? why not at 206F?

What could be wrong? is my DME confused?

BTW, how do I know if the fans are running on low or high speed? I think it's the low fan speed since relays 19 & 21 are clicking..

Thanks

Sasha

[Loren]

What are you using to measure the temperature?

I hope it is not the AC hack as that is not reliable. You need Durametric, a PST2 or PIWIS tester to accurately measure the temperatures.

[pk2]

There is quite alot of debate as to how real the guauge on your dash is. To Lorens point, to get closer to your actual temp you can buy a cheap IR temp reader(Harbor freight) and shoot it around at hot spots on your cooling circuit and engine. See if it jives with your dash gauge. If it does I'd say you nee a new fan/thermostatic sender. (Loren?)

Regards, PK

[sasha055]

I am using AC Hack to check the temperature. I thought that the temp displayed on AC Hack/Gauge is coming from DME, so even if the reading is wrong, DME should start fans at 206F, it starts them at 217.

PK, what is the fan/thermostatic sender you're talking about?

Sasha

Edited July 8, 2011 by sasha055

[Loren]

I do not know where the the temperature in the AC hack comes from - but I can tell you that it reads differently than my PST2 or PIWIS tester. Sorry, but I would not trust any of the readings from the AC hack.

I doubt there is anything wrong with your car or sensors as 11 degrees F is not that much - but a simple test with a PST2 or PIWIS would tell.

[sasha055]

Thanks a lot Loren.

I'll stop by my indy shop to check it

Sasha

[N41EF]

Most of the better OBD readers will show real time values from the DME. When I installed the low temp thermostat I used it to see how much cooler.

Also, when was the last time you cleaned your radiators out? Not an indication issue, but a real cooling issue.

[wvicary]

You are trying to fix something that is not a problem. 11 degrees F is nothing to be concerned about and there are always slight variances in sensor readings. If you had a 20 degree difference I would be worried. If the fans are working correctly and the engine isn't purging coolant then consider this normal operation of your vehicle but still monitor things for the long run.

[sasha055]

You are trying to fix something that is not a problem. 11 degrees F is nothing to be concerned about and there are always slight variances in sensor readings. If you had a 20 degree difference I would be worried. If the fans are working correctly and the engine isn't purging coolant then consider this normal operation of your vehicle but still monitor things for the long run.

That's how I noticed the problem. After a long stop&go drive from work, temp rised to end of 0 in "180". I parked the car in the garage.. 2 hr later I noticed a puddle of coolant under rear/right side. I did the tests.. my coolant boils if I park the car and coolant temp is above 103C.

I changed the coolant last year (porsche coolant 50/50), I burped the system and then drove for 2 month with bleeder valve open. I didn't loose any coolant in 8 month of winter here, so coolant tank is not broken. I have new coolant tank cap. I do suspect that my bleeder valve is not holding very well.. but not sure about that.

Thanks

Sasha

[Dale_K]

Not speaking to the issue of temps, but I was able to fix a leak that caused coolant to be released near the right rear wheel. There are 2 o-rings under the bleeder valve housing. I matched some up at the local hardware store for less than a dollar. After you take out the 8 little bolts and remove the bleeder valve cap the remaining piece actually lifts straight out but it is likely to be kind of stuck so you need to grab it with some big pliers and wiggle it a little. The o-rings loose their shape over time and won't seal. Here's a couple pics I took.

This is the part you have to lift off with some prying.

The o-rings laying loose.

[sasha055]

I did change the o rings on my bleeder valve, however it seems that the valve is loose( that how I felt it) also when I open and close the valve it doesn't snaps back.. feels like a spring( if there is one inside) is weakened.

Also, should there be a gasket of some sort between the coolant tank and valve cover (the one with the bolts)?

Sasha

[Dale_K]

No gasket on mine. I first replaced my cap and bleeder valve and only did the o-rings when I still had a leak. Actually I think my bleeder valve is OK because the new and the old felt the same. And the cap should have a part number that ends in the suffix 04 if you want to be sure you have the latest version.

Basically I don't think you have a temp problem but instead a leak problem. Put on a new cap and bleeder and see what happens. I've been seeing temps near 100 and I did for the first time see 3 drops of coolant on the garage floor this morning. I guess the hardware store o-rings aren't sealing perfectly. They certainly aren't metric o-rings.

Let me know if you want my old bleeder valve for free.

[sasha055]

No gasket on mine. I first replaced my cap and bleeder valve and only did the o-rings when I still had a leak. Actually I think my bleeder valve is OK because the new and the old felt the same. And the cap should have a part number that ends in the suffix 04 if you want to be sure you have the latest version.

Basically I don't think you have a temp problem but instead a leak problem. Put on a new cap and bleeder and see what happens. I've been seeing temps near 100 and I did for the first time see 3 drops of coolant on the garage floor this morning. I guess the hardware store o-rings aren't sealing perfectly. They certainly aren't metric o-rings.

Let me know if you want my old bleeder valve for free.

Thanks Dale! pm me your paypal address and I'll pay for shipping to 98074 and a couple beers for you.

My bleeder valve seems deformed and loose.. but I never saw another one so I have nothing to compare it to.

Sasha

ps Where did you buy new bleeder valve? I never saw them for sale separately

Edited July 10, 2011 by sasha055

[sasha055]

Update on bleeder valve:

I found a part nr for bleeder valve and ordered a new one. Part number for bleeder valve is 996.106.347.02. It was updated from .01 and price went up from 33$ to 80$.

I got one from Sunset for 59$. It comes with all parts, including o-rings and screws.

It should arrive next week. I'll post an update once installed.

Sasha

[sasha055]

Here's an update:

I replaced my bleeder valve last week, after that I drove a couple of days with it up to bleed the system a little.

Yesterday when I got back home, I wanted to close the valve, however it was stuck up, after engine (and coolant) cooled down I could close the valve normally.

I took a drive to heat the engine again and bleeder valve was up again..

Is it normal?

[logray]

Normal. Yes, it goes up on it's own when hot, then goes back down once cooled.

To lock it in place you can lift the clip up to force bleeding even on a cold vehicle.

Edited August 10, 2011 by logray

[coleta]

Does anybody know if this is actually bleeding anything? Doesn't seem like it because it's sealed and sits on top all by its self.

Can it be more of a pressure thing? higher psi when cold and then it's relieved when hot for some reason?

[logray]

Yes, the bleeder valve was designed specifically for that purpose. It isn't called "bleeder valve" for a different reason... :rolleyes:

P/N 99610634702 BLEEDER VALVE

If you think you have air in the system, it is recommended to have the coolant drained and refilled using a vacuum system, such as the Uview Airlift 55000.

[sasha055]

It does "bleed" the system.

When I changed my coolant, having the valve open and revving the car, you can see vapor coming out.

An update for my problem:

New bleeder valve is finally working correctly, no condensation.. it does stick up a bit when the coolant is hot.

However.. good news! I found where the condensation was coming from!

After some more investigations it seems that my condensation was coming from coolant cap. I have the new cap (04 version) but the threads on the tank were old, also the plastic cover that you put on the tank was kinda stopping in one of the plastic ribs on the tank which made it impossibile to screw the cap tightly.

I cut the plastic cover a little and added some PTFE tape on the threads on the tank and I finally have a working cooling system!

So if you replaced the cap and still have condensation.. look at the threads on the tank.. you might need to add some PTFE tape to it!

Thanks for all the help!

Sasha