As you may have noticed we have had some server issues since updating the software. We will be moving to a new (more powerful) server soon. I will post a notice here when we get closer to the physical move. In the meantime -- Please consider an ANNUAL donation to help keep this site operating.   Click here to Donate

Welcome to RennTech.org Community, Guest

There are many great features available to you once you register at RennTech.org
You are free to view posts here, but you must login to reply to existing posts, or to start your own new topic. Like most online communities, there are costs involved to maintain a site like this - so we encourage our members to donate. All donations go to the costs operating and maintaining this site. We prefer that guests take part in our community and we offer a lot in return to those willing to join our corner of the Porsche world. This site is 99 percent member supported (less than 1 percent comes from advertising) - so please consider an annual donation to keep this site running.

Here are some of the features available - once you register at RennTech.org

  • View Classified Ads
  • DIY Tutorials
  • Porsche TSB Listings
  • VIN Decoder
  • Special Offers
  • OBD II P-Codes
  • Paint Codes
  • Registry
  • Videos System
  • and get rid of this welcome message

It takes just a few minutes to register, and it's FREE

Contributing Members also get these additional benefits:
(you become a Contributing Member by donating money to the operation of this site)

  • No ads - advertisements are removed
  • Access the Contributors Only Forum
  • Contributing Members Only Downloads
  • Send attachments with PMs
  • All image/file storage limits are substantially increased for all Contributing Members
  • Option Codes Lookup
  • VIN Option Lookups (limited)
garyman42

986 coolant light blinking, temp at bottom of scale

19 posts in this topic

My 2001 Boxster S just started blinking the coolant light, and the temp gauge reads bottom of scale, and the coolant indicator light is on.

I checked the coolant level in the rear trunk, and it is fine.

What's up?

Share this post


Link to post
Share on other sites
    You can remove these ads by becoming a Contributing Member.

You probably have a bad connection or disconnected wire from your sensor (on the cap I think ) or the float is stuck. pk

Share this post


Link to post
Share on other sites

The blinking light is a low coolant level. If the level is fine it's a level sender issue. It isn't on the cap, it's on the bottom of the resevoir. The parts diagram show what it looks like, and the fact that most carry it, makes it seem that they fail. I'd check the wiring to it, then the sensor itself.

Share this post


Link to post
Share on other sites

Here is a photo of the coolant level sensor switch, located under the coolant reservoir:

post-6627-0-32087900-1289274932_thumb.jp

Also, keep in mind that the same warning light can also flash to indicate a fault in the engine compartment blower fan.

Regards, Maurice.

Share this post


Link to post
Share on other sites

Thanks for the responses. I'll look into the sensor connection this evening.

I noticed the blinking coolant indicator when I started the car to head home from work.

The engine should have been cool, and I should not have needed the fans.

TEMPERATURE INDICATOR:

So... any idea about the temp indicator reading at the bottom of the scale? That is definitely

not right. Also, the amber coolant idiot light is on.

I am still hoping this is a minor concern!

Cheers.

Edited by garyman42

Share this post


Link to post
Share on other sites

Four functions of the coolant warning light:

1. Engine coolant level too low

— light flashes slowly (0.5 Hz)

2. Engine compartment temperature too high

— light flashes slowly (0.5 Hz) (engine compartment blower might be faulty)

3. Engine coolant temperature too high

— light is lit; pointer on the right

4. Temperature sensor at water outlet faulty

— light flashes rapidly (1 Hz); pointer on the right

Note

The temperature warning in point three is indicated if the conditions "engine coolant temperature too high" and "engine coolant level too low" are present simultaneously 

(1Hz = 1 flash per second.  0.5Hz = 2 seconds per flash)

So it might be the temperature sensor is faulty (if the light is rapid flashing).

Share this post


Link to post
Share on other sites

Four functions of the coolant warning light:

1. Engine coolant level too low

— light flashes slowly (0.5 Hz)

2. Engine compartment temperature too high

— light flashes slowly (0.5 Hz) (engine compartment blower might be faulty)

3. Engine coolant temperature too high

— light is lit; pointer on the right

4. Temperature sensor at water outlet faulty

— light flashes rapidly (1 Hz); pointer on the right

Note

The temperature warning in point three is indicated if the conditions "engine coolant temperature too high" and "engine coolant level too low" are present simultaneously

(1Hz = 1 flash per second. 0.5Hz = 2 seconds per flash)

So it might be the temperature sensor is faulty (if the light is rapid flashing).

Hi Richard,

From my memory, the flash speed was about 1 Hz. That would be consistent with the faulty water outlet temp sensor. Seems

that would also be consistent with temp indicator at bottom of scale.

Would that also be consistent with amber coolant idiot light on the row of indicators below instrument cluster illuminated?

Thanks,

--Gary

Share this post


Link to post
Share on other sites

I think it would. A diagnostic check should show what's wrong if it is the temperature sensor which has failed.

Share this post


Link to post
Share on other sites

I think it would. A diagnostic check should show what's wrong if it is the temperature sensor which has failed.

Thanks Richard. It makes sense that a faulty sensor would drive the behavior of all three symptoms.

Is this a shop fix, or is this something I can do? Any instructions and illustrations on how to

replace the sensor?

Thanks,

--Gary

Share this post


Link to post
Share on other sites

The workshop manual makes it sound easy enough:

19 78 19 Removing and installing coolant temperature sensor

The place of installation is at the left front in the direction of travel, in the area of cylinder 4.

Removal

1. Remove rear underside panel.

2. Pull off electrical plug connection. Undo temperature sensor (wrench size 22).

post-4000-0-49286700-1289379616_thumb.jp

Installation

1. Check sealing ring and use a KD (service) sealing ring if necessary.

Note

As standard, the temperature sensor has a captive sealing ring.

Tightening torque 25 ± 5 Nm (18 ± 3.5 ftlb.)

I would be tempted to get a diagnostic check done first though. Don't want to be barking up the wrong tree.

Edited by Richard Hamilton

Share this post


Link to post
Share on other sites

The workshop manual makes it sound easy enough:

19 78 19 Removing and installing coolant temperature sensor

The place of installation is at the left front in the direction of travel, in the area of cylinder 4.

Removal

1. Remove rear underside panel.

2. Pull off electrical plug connection. Undo temperature sensor (wrench size 22).

post-4000-0-49286700-1289379616_thumb.jp

Installation

1. Check sealing ring and use a KD (service) sealing ring if necessary.

Note

As standard, the temperature sensor has a captive sealing ring.

Tightening torque 25 ± 5 Nm (18 ± 3.5 ftlb.)

I would be tempted to get a diagnostic check done first though. Don't want to be barking up the wrong tree.

Thanks again, Richard. I started it up again last night. Confirmed 1Hz blink rate on the temp indicator.

The amber light on the cluster I thought was a coolant indicator is the check engine light.

I'll get her checked out at a shop.

Cheers,

--Gary

Share this post


Link to post
Share on other sites

Final analysis - Broken wire at the coolant temperature sensor. All is well after the wire break was repaired. :)

Thanks for your help.

Share this post


Link to post
Share on other sites

My coolant light on my '99 Boxster started flashing last fall. Turning the car off and back on alleviated the problem. I check the coolant level, and it appeared to be just a smidge above Min level.

This spring, I added about 3 cups of coolant (mixed 60-40), to bring the reservoir level to about mid level. The light hasn't flashed since.

I'll have to keep an eye on it...not sure why that small amount of coolant is missing. It's almost due for a coolant flush anyway.

Share this post


Link to post
Share on other sites

check again at broad daylight your coolant level...its "hard" to see the level...the max should only be about half an inch to the top...if you can see the arrow pointing upward as the max..then see the line.....if this dont work. ...you have to check the temp sensor underneath the coolant container..

Share this post


Link to post
Share on other sites

Anyone know if you have to drain the coolant and remove the coolant reservoir to be able to replace the coolant level sensor?

Step by step on replacing this sensor would be more helpful.

Share this post


Link to post
Share on other sites

Anyone know if you have to drain the coolant and remove the coolant reservoir to be able to replace the coolant level sensor?

Step by step on replacing this sensor would be more helpful

Depending upon your year and model, you may not have to drain anything to change the level sensor (it is on the outside of the tank, yellow arrow):

Pic4.jpg

Share this post


Link to post
Share on other sites

Thank you for the reply. That's what I was thinking but last thing I want is Coolant all over the trunk. 98 Boxster - is the year.

Drain or not to Drain that is the question?

Share this post


Link to post
Share on other sites

Thank you for the reply. That's what I was thinking but last thing I want is Coolant all over the trunk. 98 Boxster - is the year.

Drain or not to Drain that is the question?

If all you are going to do is change the level sensor, no, you do not need to drain it..............

DSC00287.JPG

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now