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1

Omega General Help / Engine temperature gauge at over 100C

« on: 30 September 2017, 20:20:35 »

Hello.

I am having problems with the engine temperature in my car so I need some help.

My car:
Opel Omega B, year 1998, 5-speed manual transmission, automatic climate control, 2.0 16V X20XEV engine.

Problem:
The temperature gauge in the dashboard regularly goes to over 100 Celsius and the red temperature
symbol lights up. A few years ago when everything was working correctly, I have tested the cooling
fan activation temperature, and it was at 95C-96C. Unfortunately I didn't check whethere both fans
were spinning then or if just one was spinning. I also don't know if it was spinning at full speed
or half-speed. But I know it turned on at cca. 95C-96C.

So I decided to do this test again today to see what is happeninb. AirConditioning was turned OFF !

I turned on the car in my driveway and left it running. After about 10-15 minutes, the temperature
reached 95C. Then it was slowly rising by 1 Celsius every 1 minute and reached cca 97C-98C. The fan
still didn't turn on. Then the temperature jumped from 98C to max. (100+C-105+C) in only 5-10 seconds and
the red temperature symbol came on. Then after 15 seconds both fans (main cooler fan + AC fan)
started spinning, but I think only at half speed because it didn't look very fast to me. Is that
"stage 2", since both fans are spinning, or is it "stage 1", since they are spinning slow?

They were spinning for maybe 10-15 seconds and then they turned off. But the temperature gauge
in the dashboard was still on 100+C with glowing red symbol. I then turned off the car.

So now the question is ... is the reading in the dashboard wrong (temperature sensor displaying
wrong temperature?) or is there something wrong with the fan switches? The coolant is fresh, level is
good and there are no leaks anywhere.

Since I know that the main fan turned on at 95C in the past, it looks like "stage 1" is not activated
anymore at 95C. Or it is activated, but only later at 100+C. I'm not sure whether it is stage 1 or stage 2
because both fans start to spin, but they seem to spin slow. I'm not sure how it should be.

I used some contact cleaner on the two temperature switches on the front (on the radiator, top one
with 2-pins and bottom one with 3-pins) but it didn't make any difference. I didn't check/touch the
temperature sensors behind the engine because I could not get to them.

How do the two temperature switches in the radiator work exactly? Are they in direct contact with the coolant?
Are they controlled by the coolant temperature or by the temperature sensors behind the engine? If I wanted
to replace the two temperature switches on the radiator, would I need to drain the coolant out first ?

What are the correct "stages" ?

Stage 1: radiator fan half-speed?
Stage 2: radiator fan full-speed + AC fan half/full?

Has anyone investigated this before ? Any tips on what I should try next would be appreciated. Thanks.

Pics for reference:

2

Maintenance Guides / Cleaning the throttle valve assembly Omega 2.0 16V

« on: 05 April 2008, 10:30:11 »

This process is described for a left hand drive Opel Omega 2.0 16V, X20XEV engine (without cruise control).

This is a translation of the same post from my native language into English. I hope I didn't make too many mistakes.

I decided to document the complete process of removing, cleaning and reinstalling the throttle valve with idle control valve and idle speed stepper motor on Opel/Vauxhall Omega-B because there is no guide as complete as this on the Internet. I believe you can only really fix this properly if you remove the part and clean it thoroughly. I hate those half-done jobs cleaning things while still mounted on the car. I was performing this process during the past two days and I documented everything. Since there's 45 pictures in this guide and I don't know if the forum will accept them all I decided to upload those on a different server. So to see the pictures just view them on this link: http://users.volja.net/grebenm/plx/x20xev/x20xev.html.

By the way, "slika" means "picture" so when you see "slika_01" it means "picture_01".

The simptoms of a dirty throttle valve or idle speed stepper motor are:
- occasional jerky, erratic idle
- ocasional stalling of the engine, mostly with stepped-on clutch while the car is slowing down to a stop
- probable low power and responsivness of the engine

The assembly which needs cleaning is basically comprised of three parts:
- throttle valve (throttle body)
- idle speed stepper motor
- idle control valve

It is all located on the left side of the engine under that big air intake hose (slika_01, slika_02)

1. Disconnect the negative, minus (-) terminal of the car battery. This will cause the saved values to be lost from the computer, the time and date will be reset and probably also the car radio code will later need to be input again.

2. Remove or detach wiring harness plug from intake air temperature sensor, wiring harness plug from hot film mass air flow meter and crankcase ventilation hose from cylinder head cover. (slika_03, slika_04)

3. Release the metal clamp on the air intake hose on the side where it is mounted onto the air cleaner housing and on the side where it is mounted onto the throttle body. You can then remove the air intake hose and put it aside. (slika_05, slika_06)

4. Remove wiring harness plug from the throttle valve potentiometer and from the idle speed stepper motor. (slika_07, slika_08)

5. Detach the accelerator Bowden cable from the throttle body. First pull away the part with the rubber joint and then the part with the ball joint. I lubricated the rubber joint a bit with WD40 so it came off easier. Be careful not to lose the plastic pin behind the rubber joint. Perhaps it is worth remembering which jag it is placed on in case you take it off. I did that and later positioned it back on the same jag but I never bothered to check what exactly it's function was. Could be some sort of idle tweaker ... never mind. The ball joint on the other side of the cable has a metal splint in it. You have to remove that before you can pull the ball off. It could be wise to use a drop of oil to lubricate the joint so get it off easier. I've had major problems getting the thing off. It just wouldn't go. I had to use a screwdriver and a hammer and hit it a few times. In this case you have to be careful not to bend the metal arm on which the joint is mounted and you have to be careful not to damage or destroy the ball joint itself. I managed to leave quite a few dents on it. (slika_09, slika_10, slika_11)

6. Remove the fastening clamp for fuel distributor pipe adapter from accelerator Bowden cable bracket / throttle body. (slika_12)

7. Remove fuel supply line from fuel distributor pipe adapter. Counterhold (fixate) at fuel distributor pipe adapter with 17mm wrench and unscrew the fuel supply line with 19mm wrench. Expect a few drops of fuel from the supply line after you remove it (have a rag ready to capture it). (slika_13)

8. Detach coolant hoses from throttle body. I did not have any escaping coolant from these lines but it may be wise to be prepared anyway. (slika_14)

9. Detach vacuum hose for tank vent valve from throttle body. (slika_15)

10. Remove 4 fastening bolts with which the throttle body is attached to the intake manifold and remove the throttle valve. Be careful not to drop anything into the intake manifold hole as it can cause severe engine damage. Also remove the gasket. You will replace this with a new one later (gasket: intake manifold to throttle body, part number: 90412686, catalogue number: 8 28 466) (0.64 EURO). (slika_16, slika_17, slika_18)

11. Put the throttle valve assembly on the table and first remove the throttle valve potentiometer (black thingie) and put it aside. Then remove the right part of the assembly which is the idle control valve and the idle speed stepper motor (solenoid). There is another gasket there which you should also throw away and later replace with a new one (gasket: throttle body to idle control valve, part number: 9240103, catalogue number: 8 37 302) (2.89 EURO). Now take the valve you just removed from the throttle body and take off the idle speed stepper motor (solenoid), that's the part with the black connector on it. Be careful not to lose the black rubber gasket there. You will then have all three parts of the whole assembly on the table. I call the idle speed stepper motor a solenoid because I believe that the thing doesn't really turn or spin but rather pushes the rod inside the idle control valve up and down (in and out). If you hold the solenoid assembly and shake it along it's axis you will hear the clicking of the solenoid inside moving up and down. The throttle valve potentiometer itself does not need any cleaning.

3

Omega General Help / [m by=Auto_Addict destboard=omegaguides dest=1207387811]: Cleaning the throttle valve assembly, complete

« on: 05 April 2008, 12:42:27 »

[moved] [link=http://www.omegaowners.com/forum/YaBB.pl?num=1207387811/0]Maintenance Guides[/link] [move by] Auto Addict.