SaturnFans.com
what's new (beta) - classifieds - forums - photos


Go Back   SaturnFans.com Forums > Models > Saturn S-Series > S-Series Tech
Register FAQ Members List Groups Calendar Chat Room Search Today's Posts Mark Forums Read

Reply
 
Thread Tools Display Modes
Old 03-03-2014, 04:20 AM   #1
ReggieFisher
New Member
ReggieFisher is on a distinguished road
 
Join Date: Oct 2013
Posts: 2
Default Please help me better understand/troubleshoot engine cooling system (2000 SL1)

HI All,

First of all, thanks for all the information and advice. This is the first time I'm having to post because usually almost all my questions have already been asked and answered by people on this board--Including fixes my (former-) mechanic could't solve.

2000 SL1, 150k miles

So the symptoms of the problem:
1. random stall(s) on one hot morning a few months ago (I think I was running the AC at the time). Occasional low idle at stop lights. Things seem to improve when I run the heater on med/high.
2. Temp gauge goes to 1/4 and stops.

In reading posts here, that would seem to indicate a bad thermostat. I can take a stab a replacing it--what is the best aftermarket replacement (I've seen some posts about 180 vs 195 degrees etc, but they were older) ?

But in general, just to help me understand:
There's the two-wire ETCS, a one-wire temp sensor, and the thermostat, correct?

The ETCS (which I long ago replaced with the copper tipped one) gives temp info to the PCM, but where is that info used from there?

The one-wire sensor goes straight to the dash gauge? So if the gauge doesn't move at all, this is where to look for a problem?

The thermostat seems to be a themo-mechanical actuator that doesn't take any electrical input. It just opens and closes (driven by engine temp) to allow more or less coolant into the engine?

Thanks for any input.

REWARD EXCELLENCE!

Add to ReggieFisher's Reputation
Rate the quality of this post and help ReggieFisher reputation points. Click the reputation button near the bottom left corner of this message box. Thank you!
ReggieFisher is offline   Reply With Quote
SaturnFans.com Sponsored Links
Old 03-03-2014, 06:22 AM   #2
Signmaster
Master Member
Signmaster is a name known to allSignmaster is a name known to allSignmaster is a name known to allSignmaster is a name known to allSignmaster is a name known to allSignmaster is a name known to all
 
Join Date: Jan 2007
Location: Virginia Beach, VA
Posts: 5,900
 

1995 SL1
Default Re: Please help me better understand/troubleshoot engine cooling system (2000 SL1)

You have the basic idea correct, but are a little off target on a couple of issues.

The two wire ECTS you have correct. On your car this operates the gauge as well (through the PCM), and impacts the mixture of the engine.

The single wire gauge sensor is on earlier cars only, so your car won't have one.

The thermostat controls flow to the radiator. Flow always takes place within the engine loops, including the heater core and reservoir. As the engine gets hot, the thermostat allows flow to the radiator to cool the coolant mixture down to a reasonable temp.



As for thermostats... what is best? A thermostat. I'm sure someone will come along and tell you that only a Stant thermostat should be used. My car didn't come with one, nor was the replacement a Stant unit. The vast majority of thermostats will work, but keep in mind that some use a unique thermostat housing. That is usually the units that come with a housing. If you purchase one of those units, make sure to keep the stock housing currently on your car, just in case you switch back at some point.

Thermostat ratings vary, so don't be surprised to see temp ratings of 185-200 or so degrees. Most operate about the same in reality. You can find different ratings for the exact same thermostat in many cases, so don't sweat the little stuff. Though many will tell you warmer is better, I don't personally agree. The move to the warmer thermostat on our '95 (along with the recommended spark plug) resulted in an MPG loss on our car.

The service manuals specify a range, not an exact. IIRC the starts to open range is 84-88C, and the service limits is a little broader.

These cars don't have precision instruments, so if you are concerned with actual operating temp find someone with a reader or scangauge that can confirm your actual temp vs gauge position.


It sounds like in your case you have a low idle issue. You can check your IAC (idle air control) for proper function by removing the intake hose and placing your finger over the hole in the throttle body while the car is running. The car should drop to a low idle, roughly 500 RPM. This is at full operating temp. In some cases the low idle throttle stop screw has been moved, or the wear on the car requires that it be adjusted.

If you have never cleaned out your throttle body, there is a chance that all the extra gunk in there is allowing the occasional stall due to clogged passages, restricted or inconsistent flow through the throttle blade, etc. A good cleaning might be in order.


My guess is that the use of the heater is cooling the engine down enough that your mixture is being moved to richer via the ECTS. Richer mixture, higher idle, no stall.

Last edited by Signmaster; 03-03-2014 at 06:36 AM..

REWARD EXCELLENCE!

Add to Signmaster's Reputation
Rate the quality of this post and help Signmaster reputation points. Click the reputation button near the bottom left corner of this message box. Thank you!
Signmaster is offline   Reply With Quote
Old 03-04-2014, 01:18 AM   #3
el diablo viejo
Senior Member
el diablo viejo will become famous soon enough
 
el diablo viejo's Avatar
 
Join Date: Jan 2012
Location: New Hampshire
Posts: 1,419

1994 SW1
2000 SW2
Default Re: Please help me better understand/troubleshoot engine cooling system (2000 SL1)

^^^ +1 All good. Most members go with the Stant # 14279 195F because it will fit in the factory housing, has a good performance record and is easy to find. If you happen to like another tstat, it's no big deal.
You might also want to check or replace the iats ( same part as the ects ) and air filter, and check the air intake tube.

...
97 sl2 a/t 104 K
1989 GMC 3500 454 129 K, 1969 442 455 rat rod

REWARD EXCELLENCE!

Add to el diablo viejo's Reputation
Rate the quality of this post and help el diablo viejo reputation points. Click the reputation button near the bottom left corner of this message box. Thank you!
el diablo viejo is offline   Reply With Quote
Old 03-04-2014, 03:53 AM   #4
ReggieFisher
New Member
ReggieFisher is on a distinguished road
 
Join Date: Oct 2013
Posts: 2
Default Re: Please help me better understand/troubleshoot engine cooling system (2000 SL1)

Thanks both for the information.

I'll pick up the Stant if I can find it; otherwise, whatever is available.

I cleaned out the throttle body and EGR valve after the stall: they weren't terrible, but did have some build up. At least, I haven't stalled again since then.

The low idle still makes me nervous so I'll check the air intake hose. I had the air intake manifold gasket changed at my last service (6mo ago), but per some advice here, I tested it by spraying around the seam while idling and it did change the idle. Does that mean they could have installed it incorrectly (e.g. pinched)?

REWARD EXCELLENCE!

Add to ReggieFisher's Reputation
Rate the quality of this post and help ReggieFisher reputation points. Click the reputation button near the bottom left corner of this message box. Thank you!
ReggieFisher is offline   Reply With Quote
Old 03-04-2014, 12:21 PM   #5
OldNuc
Super Member
OldNuc has a brilliant futureOldNuc has a brilliant futureOldNuc has a brilliant futureOldNuc has a brilliant futureOldNuc has a brilliant futureOldNuc has a brilliant futureOldNuc has a brilliant futureOldNuc has a brilliant futureOldNuc has a brilliant futureOldNuc has a brilliant futureOldNuc has a brilliant future
 
Join Date: Apr 2008
Location: Far Southwestern Iowa
Posts: 63,242
 

1998 SC2
Default Re: Please help me better understand/troubleshoot engine cooling system (2000 SL1)

Do not buy one of the thermostat plus new housing units as they are undersized and do not meet OEM specifications.

Buy your parts from RockAuto as it will be considerably cheaper. http://www.rockauto.com/ They have the STANT 14279 thermostat and if it is not listed under your car then use the manufacturer part number tab to find it.

I see your question on how the cooling system functions was not answered.
In the S-Series cooling system there are 4 separate cooling flow loops, 3 external and 1 internal loop. These loops are in parallel with each other and all terminate at the water pump suction and the water pump provides the driving force to the coolant flow in all loops.

1) The deaeration line flow is from the water pump discharge into the block up into the head to the high point of the head(SOHC) or intake manifold(DOHC) to the reservoir then from the reservoir to the pump suction. Flow in this loop is continuous.

2) Heater loop flow is from the water pump discharge into the block up into the head to manifold to heater core to the pump suction and the reservoir also sits on this heater loop line. Flow in this loop is continuous.

3) Internal loop flow is from the water pump discharge into the block up into the head and back down from the head area through an internal passage to the pump suction. Flow in this loop is control ed by the thermostat.

4) The radiator loop flow is from the water pump discharge into the block up into the head and out the head outlet into the radiator and back to the pump suction. Flow in this loop is controlled by the thermostat.


The radiator loop(4) and internal loop(3) flow are both controlled simultaneously by the thermostat. As the radiator loop flow increases the internal loop flow decreases. The disk on the back end of the thermostat is what moves to close the internal loop as the radiator loop flow opens. Both thermostat disks move in the same direction, one is opening increasing loop flow as the other is closing reducing loop flow.

The total cooling system flow passes the ECTS so you should always know what the bulk coolant temperature is. The thermostat control element is sensing the coolant temperature in the water pump suction chamber.

http://www.saturnfans.com/photos/sho...ng-s/cat/12963


Saturn 96 model year and newer temperature gauge reading vs. actual temperature as read from the ECTS.

GAGE Reading..........ECTS Temperature..........Event
.....1/4.................................150 F
.....3/8.................................192 F...................T-stat cracks open
.....3/8+................................195 F
.....1/2.................................212 F
.....9/16................................221 F...................Fan ON
.....7/16................................210 F...................Fan OFF coast to 205 F

The installed thermostat is marked as 87 C

Add 1/8 to the gauge reading column to obtain the corresponding gauge indication for Saturn 95 model year and older.

REWARD EXCELLENCE!

Add to OldNuc's Reputation
Rate the quality of this post and help OldNuc reputation points. Click the reputation button near the bottom left corner of this message box. Thank you!
OldNuc is offline   Reply With Quote
Old 03-04-2014, 12:44 PM   #6
madpogue
Super Member
madpogue has much to be proud ofmadpogue has much to be proud ofmadpogue has much to be proud ofmadpogue has much to be proud ofmadpogue has much to be proud ofmadpogue has much to be proud ofmadpogue has much to be proud ofmadpogue has much to be proud of
 
Join Date: Sep 2004
Location: Madison, WI USA
Posts: 25,713
 

1996 SW2
Default Re: Please help me better understand/troubleshoot engine cooling system (2000 SL1)

Quote:
Originally Posted by ReggieFisher View Post
The thermostat seems to be a themo-mechanical actuator that doesn't take any electrical input. It just opens and closes (driven by engine temp) to allow more or less coolant into the engine?
Just an FYI, this is the definition of an automotive thermostat. Your Saturn is nothing special wrt. this. The only variation is that with newer vehicles (including our cars), as the passage to the radiator opens, a bypass closes. Thermostats in many old-school systems simply opened or closed the flow to the radiator.

REWARD EXCELLENCE!

Add to madpogue's Reputation
Rate the quality of this post and help madpogue reputation points. Click the reputation button near the bottom left corner of this message box. Thank you!
madpogue is offline   Reply With Quote
Old 03-04-2014, 01:28 PM   #7
OldNuc
Super Member
OldNuc has a brilliant futureOldNuc has a brilliant futureOldNuc has a brilliant futureOldNuc has a brilliant futureOldNuc has a brilliant futureOldNuc has a brilliant futureOldNuc has a brilliant futureOldNuc has a brilliant futureOldNuc has a brilliant futureOldNuc has a brilliant futureOldNuc has a brilliant future
 
Join Date: Apr 2008
Location: Far Southwestern Iowa
Posts: 63,242
 

1998 SC2
Default Re: Please help me better understand/troubleshoot engine cooling system (2000 SL1)

If you are inquiring about the temp chart, that is what your temperature gauge for the various engine coolant temperatures.

REWARD EXCELLENCE!

Add to OldNuc's Reputation
Rate the quality of this post and help OldNuc reputation points. Click the reputation button near the bottom left corner of this message box. Thank you!
OldNuc is offline   Reply With Quote
Old 03-04-2014, 03:31 PM   #8
Signmaster
Master Member
Signmaster is a name known to allSignmaster is a name known to allSignmaster is a name known to allSignmaster is a name known to allSignmaster is a name known to allSignmaster is a name known to all
 
Join Date: Jan 2007
Location: Virginia Beach, VA
Posts: 5,900
 

1995 SL1
Default Re: Please help me better understand/troubleshoot engine cooling system (2000 SL1)

OEM spec for a thermostat housing? Now that's funny scare tactics there!

It's a thermostat. The vast majority work. Some fail.


Those who don't learn from history...

...are bound to repeat it!

REWARD EXCELLENCE!

Add to Signmaster's Reputation
Rate the quality of this post and help Signmaster reputation points. Click the reputation button near the bottom left corner of this message box. Thank you!
Signmaster is offline   Reply With Quote
Old 03-04-2014, 03:33 PM   #9
Signmaster
Master Member
Signmaster is a name known to allSignmaster is a name known to allSignmaster is a name known to allSignmaster is a name known to allSignmaster is a name known to allSignmaster is a name known to all
 
Join Date: Jan 2007
Location: Virginia Beach, VA
Posts: 5,900
 

1995 SL1
Default Re: Please help me better understand/troubleshoot engine cooling system (2000 SL1)

Quote:
Originally Posted by ReggieFisher View Post
Thanks both for the information.

I'll pick up the Stant if I can find it; otherwise, whatever is available.

I cleaned out the throttle body and EGR valve after the stall: they weren't terrible, but did have some build up. At least, I haven't stalled again since then.

The low idle still makes me nervous so I'll check the air intake hose. I had the air intake manifold gasket changed at my last service (6mo ago), but per some advice here, I tested it by spraying around the seam while idling and it did change the idle. Does that mean they could have installed it incorrectly (e.g. pinched)?
It sounds to me like they didn't install it correctly. That shouldn't be happening if they properly installed a new gasket. I'd have them do it over.

REWARD EXCELLENCE!

Add to Signmaster's Reputation
Rate the quality of this post and help Signmaster reputation points. Click the reputation button near the bottom left corner of this message box. Thank you!
Signmaster is offline   Reply With Quote
Old 03-04-2014, 06:38 PM   #10
OldNuc
Super Member
OldNuc has a brilliant futureOldNuc has a brilliant futureOldNuc has a brilliant futureOldNuc has a brilliant futureOldNuc has a brilliant futureOldNuc has a brilliant futureOldNuc has a brilliant futureOldNuc has a brilliant futureOldNuc has a brilliant futureOldNuc has a brilliant futureOldNuc has a brilliant future
 
Join Date: Apr 2008
Location: Far Southwestern Iowa
Posts: 63,242
 

1998 SC2
Default Re: Please help me better understand/troubleshoot engine cooling system (2000 SL1)

Yes, there is a spec for every part in the car so quit spreading FUD.
Quote:
Originally Posted by Signmaster View Post
OEM spec for a thermostat housing? Now that's funny scare tactics there!

It's a thermostat. The vast majority work. Some fail.


Those who don't learn from history...

...are bound to repeat it!

REWARD EXCELLENCE!

Add to OldNuc's Reputation
Rate the quality of this post and help OldNuc reputation points. Click the reputation button near the bottom left corner of this message box. Thank you!
OldNuc is offline   Reply With Quote
Old 03-04-2014, 06:43 PM   #11
OldNuc
Super Member
OldNuc has a brilliant futureOldNuc has a brilliant futureOldNuc has a brilliant futureOldNuc has a brilliant futureOldNuc has a brilliant futureOldNuc has a brilliant futureOldNuc has a brilliant futureOldNuc has a brilliant futureOldNuc has a brilliant futureOldNuc has a brilliant futureOldNuc has a brilliant future
 
Join Date: Apr 2008
Location: Far Southwestern Iowa
Posts: 63,242
 

1998 SC2
Default Re: Please help me better understand/troubleshoot engine cooling system (2000 SL1)

Quote:
Originally Posted by ReggieFisher View Post
...
The low idle still makes me nervous so I'll check the air intake hose. I had the air intake manifold gasket changed at my last service (6mo ago), but per some advice here, I tested it by spraying around the seam while idling and it did change the idle. Does that mean they could have installed it incorrectly (e.g. pinched)?
Most likely. Just go buy a new gasket and install it yourself. Do not over tighten the bolts though, just snug will do it. Just go to the local parts store and ask for one of these gaskets or equivalent. FEL-PRO Part # 61177 The FelPro is a preferred brand if they have it or Victor if not.

REWARD EXCELLENCE!

Add to OldNuc's Reputation
Rate the quality of this post and help OldNuc reputation points. Click the reputation button near the bottom left corner of this message box. Thank you!
OldNuc is offline   Reply With Quote
Old 03-04-2014, 10:08 PM   #12
Signmaster
Master Member
Signmaster is a name known to allSignmaster is a name known to allSignmaster is a name known to allSignmaster is a name known to allSignmaster is a name known to allSignmaster is a name known to all
 
Join Date: Jan 2007
Location: Virginia Beach, VA
Posts: 5,900
 

1995 SL1
Default Re: Please help me better understand/troubleshoot engine cooling system (2000 SL1)

Quote:
Originally Posted by OldNuc View Post
Yes, there is a spec for every part in the car so quit spreading FUD.
And anyone with a brain knows that the thermostat housing spec isn't going to affect operation with the correct thermostat in place. Why you try to convince people that a thermostat that has a record of failures is the best unit is beyond me. I've seen far fewer failures reported on these forums by members using other brands.

My advice would be do not believe for a second that only a single part number works. Especially when that part number has no better track record than the other options.


Care to quote that thermostat housing specification from the FSM?

REWARD EXCELLENCE!

Add to Signmaster's Reputation
Rate the quality of this post and help Signmaster reputation points. Click the reputation button near the bottom left corner of this message box. Thank you!
Signmaster is offline   Reply With Quote
Reply



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
2000 LW1 - Help with fans / cooling system bigcougar L-Series Tech 4 07-20-2012 10:52 PM
2000 Saturn SL2 Cooling System toddsrams S-Series Tech 6 10-21-2011 11:19 PM
I finally understand the A/C system! RobertGary1 S-Series Tech 2 05-16-2008 01:24 PM
To Troubleshoot Cooling Fan dlczrx S-Series General 0 07-03-2006 01:29 PM
2000 SL Manual Steering System for Power System: Trade Ya! aafreen Classifieds 0 01-06-2005 12:16 AM


All times are GMT -5. The time now is 07:05 PM.

Advanced Forum Search | Advanced Photo Search


Powered by vBulletin® Version 3.8.9
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
SaturnFans.com. The Saturn Enthusiasts Site.