A4 1.9 TDI 03 engine not warming up.

[Dubbs75]

Hi guys,
New member here, so be gentle. I've had my A4 for about a week and a half. Most of my journeys are up and down the motorway for about 25 miles. This I believe should be plenty of time for the engine to reach 90 degrees, but it was hovering around 70. Looking online it suggests that the temp should be 90 degrees and the problem should be the thermostat. So I took it to a garage yesterday and they confirmed an issue with the stat so it was changed. Now the temperature bearly gets above 50 degrees so I took it back to the garage and the guy said it's fine, but I'm concerned this is not the case. Have you guys seen this problem before? Any suggestions welcome!

[Rob69]

coolant temperature sender would be the next thing to check / change. the garage is fobbing you off at 50 degrees, it should sit bang on 90 after about 10 minutes driving.
previously did you find the temperature would creep up towards 90 in traffic but then drop off once you were on the motorway with good airflow through the radiator, that would point towards the stat having failed ? Also recheck your coolant level and that heat comes out of the heater vents as the heater matrix can get airlocked after coolant draining.

[Col]

Yes, as Rob has mentioned, the coolant sensors are notorious for their unreliability.

For future refernce and to anyone else who reads this; If there are temperature gauge problems, it is good practice whilst the system is drained down, to replace both the thermostat and the coolant temp sensor. It saves having to do the job twice.

For a lot of garages this is not in their best interest as they will be able to charge another hours labour for another simple job. A good garage will at least have the conversation with you and advise changing both so you can make a decision.

[Dubbs75]

No matter how I was driving, be it on the motorway or town driving the temperature would never get above 70, it was always 60 to 70. I'll check the levels and heaters just in case but they were all good a few days ago.

[Rob69]

they may have been good a few days ago but the garage drained the system yesterday - otherwise pointing towards a faulty CTS then.

[Dubbs75]

Ok, I'll check them this afternoon. Sorry but what's a CTS?

Ok it stands for Coolant Temperature Sensor doesn't it.

[Dubbs75]

Right I've checked the levels, everything is ok there.

[arman123]

A scan should show if the CTS is faulty i always thought if the temp needle was erratic it would point to CTS anyway as for the stat did you fit genuine most likely the tabs on the housing were broken so stat is not sitting properly on engine leaking coolant and overcoolimg you engine so when the garage did it ask them were the tabs on the housing broken if yes then replace the housing genuine stat and o ring and genuine CTS and you would be fine






Turn thermostat -item 2- approx. 90° (1/4 turn) anti-clockwise -arrow- and remove it from hose connection.




–
Remove O-ring -1-.




Installing




Installation is carried out in the reverse order; note the following:


http://workshop-manuals.com/audi/css/images/hinweis.gif Note


Renew O-ring.




–
Clean and smoothen sealing surface for O-ring as required.




http://workshop-manuals.com/audi/a4_mk2/images/a4-10827.png






–
Insert thermostat -3- with new O-ring -2- into hose connection -1-.




l
When inserting, the cross-piece on the thermostat should be horizontal as shown in the illustration.




–
Then turn thermostat 90° (1/4 of a turn) clockwise.




–
Lubricate O-ring with coolant additive.




–
Fill cooling system → Anchor (http://ctrl:IDREF=idp57936/).




Tightening torque




http://workshop-manuals.com/audi/a4_mk2/images/a4-10828.png

[Dubbs75]

To be honest no i didn't ask for genuine replacement stat. I'm certainly no petrol (or in this case diesel)head! Been sitting in traffic tonight for about 20 mins. Temperature went up to 70 degrees so maybe it is overcooling the engine? Guess it'll have to go back to the garage and put on a diagnostic.

[rowdy-999]

Changing the CTS is a 10 min job.
You may lose a few 100mls of fluid. Do that and take it from there.

[Dubbs75]

I'll get it done at the weekend hopefully and let you know the outcome.

[Dubbs75]

One other thing which might be useful information, I started the car from cold last night and the fan came on straight away. Another indication of the CTS being faulty?

[Dubbs75]

Now getting a bit fed up. Taking my dad to the hospital today, the ESP light came on, then the heater coil light was blinking. Lost power, and stopped. Turned engine off, restarted and everything was ok for about 10 seconds. Then the same thing happened. A mechanic came out, saw 3 error codes. One for a strange reading from the accelerator pedal, one from the CTS, and one from a solenoid on the engine mount. He cleared them and tried to replicate the issue but to no avail. He did see one of the sensor plugs near the stat wasn't sitting right and said this may have been the problem. The clip doesn't seem to be retaining well so he cable tied it and advised it be replaced asap. Oh and the fan is still constantly on.

[arman123]

do a scan with VCDS and post the faults codes on here

[Dubbs75]

Can I get a VCDS from somewhere like Halfords? Saw a Foxwell nt200, will this do the job? Mind you it says cars made after 2004. Mines 2003.

[arman123]

No you can't look for a vw or Audi independent who will have it

[arman123]

Or post here VCDS - Users Locations (http://www.vwaudiforum.co.uk/forum/forumdisplay.php/257-VCDS-Users-Locations)
and see if anybody around you can help

[nevo]

Dont waste your time on those scanners,firstly the engine mount is very common and ignore,get a genuine cts from audi and fit,you've gone into limp mode so find someone with vcds near you and get a full scan if it repeats going into limp mode.

[MalR]

I had the same issue. Tried CTS and two stats but temperature would not get to 90. Then I changed the housing and all is well now. So change the housing and use a genuine stat when you do it again.

[Dubbs75]

I had the same issue. Tried CTS and two stats but temperature would not get to 90. Then I changed the housing and all is well now. So change the housing and use a genuine stat when you do it again.

Was your fan constantly on too? Even from cold? Sorry for being a bit thick, but what housing did you change?

[MalR]

No, fans operated correctly for me. I am talking about the thermostat housing. It's around £10 from Audi. Thermostat is around £40 from Audi too.

The problem I think is when you take the old stat off to replace it, the housing tabs tend to break. So change the housing as well.

If your fans are working all the time, might be related to CTS.

[Dubbs75]

Ok, cheers. I'm going to have to leave it till the weekend before I can get to a garage. Bit apprehensive about having to drive it up and down the motorway till then. Was a bit of a shock when it died on me today!

[Dubbs75]

Another issue! The ABS and ESP lights came on during the trip home. Drove ok but wasn't sure if id have another power loss. Made it home, did a little research and it appears to be the break light switch which is causing those lights to come on. Is it OK to drive with those lights on tonight and get it fixed tomorrow?

[Rob69]

Think it's more likely to be an ABS sensor or cable than the switch, how did you reckon it might be the switch? You won't have functioning ABS while the light is on.

[Dubbs75]

Googled it. Turn ignition off and it clears the lights. Can make it happen again by pressing the brake pedal.

[Rob69]

fair enough - I've had to do a pedal switch on the touran and polo, seems to be a common enough failure but cheap fix.

[Dubbs75]

So if it's the brake pedal switch can I drive it? Only reason I ask is my daughter is currently at a concert 30 odd miles away and I was supposed to pick her up, might be a taxi instead!

[Rob69]

Sorry bud, can't answer that one for you , your call.

If it was me though, and I was confident it was the switch and everything else was ok brake wise, I probably would.
Does that cover my **** enough ???

[Dubbs75]

Fair enough mate. I'm probably not going to risk it. Knowing how things are going at the moment, it'd only break down on me!

[Dubbs75]

Got some codes.
P1586 left/ right hydrolic sensor

00526 brake switch

Garage want £580 Inc labour for the hydraulic sensors. Said they can't just replace those, it's a whole unit. I'm not convinced so going to a different garage tomorrow. I still think it's the brake pedal switch.

[nevo]

P1586 is the engine mount solenoid,change the brake light switch,give that garage a wide berth.

[Rob69]

P1586 is for the engine mount solenoids, stiffens them up at certain engine speeds I think, from what i've seen these would be low on my list of things to spend 500 notes on at the moment
Brake switch was 11 quid from TPS last time I did one on a fabia.
have a nice weekend !!

[Dubbs75]

So it's nothing worth doing the engine mount solenoids then? I was going to have the brake pedal switch done. Surprisingly the garage said to do the mount first!

[nevo]

Its there for a reason obviously,but unless your engine's jumping around you can leave it ,its up to you.

[Dubbs75]

It's not jumping around so I'll leave it for now and just do the pedal sensor, and as Rob said 500 quid seems expensive.

[Dubbs75]

Ok new garage this morning. Scan showed the following :-01314 engine control module 79-10 please check fault codes intermittent. 00526 brake light switch-f 27-10 implausible signal intermittent. They are going to change the brake sensor today and we'll take it from there. Said the other code may be related to the first one?