Oh No another mk2 VRS (2011) Over heating issues

[Mrr4nd411]

On 16/09/2021 at 20:48, sepulchrave said:

Let us know how you get on.

Okay here goes…

 

removed thermostats:

front thermostat appears in good order, no buildup on it removed anyway

 

rear thermostat had lots of white calcium buildup on it.. and the coolant sat behind the plunger was white.. assuming previous owner kept topping it up with tap water.. thermostat removed

 

I cleaned the housings, light dusting of o-ring grease, and refitted,

 

Fresh coolant goes in and bled the system (took ages but I think it’s bled now)

 

not getting hot air in cabin (slightly warm), I can only assume this has to do with not having thermostats to restrict coolant in certain directions to properly flow to the heater core, not majorly concerned.

 

results:

coolant temp is absolutely solid now at 90, no concerns about the coolant not flowing properly etc, also no obvious loss of coolant so far (several short drives and a 40-45minute motorway trip

 

However oil temp is still concerning me, it got up to 107 on a steep uphill 50mph burst and was around 105 motorway cruising, I understand this could be sensor deviation but I’m still concerned about the oil that’s in the car, I would have changed the oil today but couldn’t get my hands on a filter and didn’t see the point in changing it without fitting a new filter,

 

Also did a combustion test again, no sign of HG leak, even tested to tester on the exhaust to make sure it was working and it is!

 

This is my update for now, I have a 40 minute trip to make on Tuesday, hopefully it’s another successful journey.

 

I feel like I’m getting closer to resolving this!

 

thanks

Tom

[Kobayashi]

Does the manual oil temp gauge move from 90c ie past the 50% mark ,as I've seen mine at 107c on digital but it has never moved from 90C

[Kobayashi]

Not my car but someone with yeti same problem  but running cool only showing 75c

[Mrr4nd411]

26 minutes ago, Kobayashi said:

Does the manual oil temp gauge move from 90c ie past the 50% mark ,as I've seen mine at 107c on digital but it has never moved from 90C

No, the coolant temp gauge sits perfectly at 90degC, the digital oil temp get up to 107degc, I’ve been driving it gently though, i haven’t tried hard acceleration yet, going to try a few more gentle drives before I test it more, still think the oil is getting hotter than it should be 

[sepulchrave]

Don't worry about that oil temperature, modern synthetics are fine at temperatures that would have turned mineral oils into a penetrant and you're nowhere near that.

[J.R.]

At what temperature does it become a problem for the long life full synthetic VAG compatible oils.

 

I am doing frequent removal runs with a very heavily loaded trailer with a large frontal area, car has been remapped so power no problem and on long autoroute inclines at full throttle I keep an eye on the oil temperature, it will exceed 120°c peaking at say 125°c before dropping to 110°c on the flat.

 

On a dry sumped bike engined racecar doing endurance races on short twisty circuits like Lydden or Brands Hatch club circuit the oil cooler could not cope and the oil temp would gradually rise lap by lap, I saw 160°c before running the crankshaft bearings but the engine was doing 11000 rpm, I hope an understressed (by comparison) lazy diesel road engine at 2 - 2.5k rpm would tolerate a higher oil temperature but at what point does the oil degrade?

[Mrr4nd411]

As I understand it around 145degc is when a synthetic will degrade, don’t take my word for it, this is just what I have read, in my case I believe my engine with little load shouldn’t be running so hot, even if it’s not doing damage to the oil I still feel there is something not quite right. Especially when people with the same engine are reporting much lower temps.

 

sounds like your car is working properly, if you run the car unloaded would the temps be between 90 and 100 on the flat? 

 

Hopefully an oil change for me will answer my question or create many more.

 

[sepulchrave]

That's a good catch with the thermostat, having run engines on the dyno I don't like to see oil temps much above 120 degrees because hot spots will be getting marginal, whatever you do don't even think about oil temperatures on the turbo return or you'll have a full on nervous breakdown and need a different forum!

[Mrr4nd411]

15 minutes ago, sepulchrave said:

That's a good catch with the thermostat, having run engines on the dyno I don't like to see oil temps much above 120 degrees because hot spots will be getting marginal, whatever you do don't even think about oil temperatures on the turbo return or you'll have a full on nervous breakdown and need a different forum!

Thanks! I promise I won’t look!

 

been reading up on people saying A car shouldn’t even be reaching 90degC coolant without thermostats..

tempted to pull all the hoses and the rad and flush them through, make sure there’s no blockages,

 

didn’t notice any expanded hoses when I was poking around after it was up to temp so I’m thinking they don’t need replacing.

 

[J.R.]

90°c is the minimum desired oil operating temperature for me, it can take several miles in winter conditions to hit it

1 hour ago, Mrr4nd411 said:

 

 

sounds like your car is working properly, if you run the car unloaded would the temps be between 90 and 100 on the flat? 

 

 

 

The figures that you quoted before seem perfectly normal to me after a couple of months of obsessively watching the oil temperature.

 

Other than a short run in winter conditions I look for my engine to reach and stabilise at 90°c oil temperature, it usually reaches this just before the water temp guage hits the middle position, in hot weather its higher and cruising on part throttle on a motorway would be around 100°c.

[Breezy_Pete]

7 hours ago, Mrr4nd411 said:

Thanks! I promise I won’t look!

 

been reading up on people saying A car shouldn’t even be reaching 90degC coolant without thermostats..

tempted to pull all the hoses and the rad and flush them through, make sure there’s no blockages,

 

didn’t notice any expanded hoses when I was poking around after it was up to temp so I’m thinking they don’t need replacing.

 

The coolant temperature gauge is 'tweaked' in software to read 90C over a 'generous' temperature range to soothe customers who might worry, so the real coolant temp may well be rather less.

You could do with some sort of scan tool reading live data. That could show you coolant temperature as read by sensor/engine ECU before software sanitisation in the cluster. You really need to get thermostats back in there at some point though.

[Mrr4nd411]

@Wino yeah I think I have some data logging ability, I’ll see what I can do, yes the plan is to replace the thermostats especially before winter, while I’m on a fault finding mission it can stay as it is, I don’t do many journeys at the moment, but will hopefully have it sorted before I need to start working in the office again 

[Breezy_Pete]

Maybe the oil cooler would be a good thing to check for coolant blockage/flow. I assume there is one.

[Mrr4nd411]

4 hours ago, Wino said:

Maybe the oil cooler would be a good thing to check for coolant blockage/flow. I assume there is one.

While I believe I have the temps more under control now I might be treading on my own toes, without thermostats I am not getting enough flow to the heater core, not too concerned however looking at the coolant diagram I may not be getting enough flow to the oil cooler either.

 

at this point I’m probably over thinking everything and I’m just writing my random rambling thoughts in this forum but only having the time to work on the car once a week for 6 hours means I’ve got far more time to think about the problem than actually solve it 😓

[Breezy_Pete]

It looks like a horribly complex system to fault find, so maybe the more thought the better.

Get that oil changed next though, and see what difference (if any) that makes to the oil temps.

Edited 20 September, 2021 by Wino

[sepulchrave]

It doesn't help that the oil cooler is directly after the turbo in the flow diagram, the obvious answer is simply to replace both thermostats with new ones for the avoidance of doubt, since all the other parts of the system are working.

[Mrr4nd411]

So today had another successful trip and a less successful return trip..

(40mins there, 50mins back)
no over heating at all on either trip though!! Which is a biiiig improvement, max 95degC oil temp both ways

On the way there I drove very gently, but still did the speed limit (probably 10 mins or so at 70mph) didn’t loose a drop of coolant!

 

on the way back I spent less time at 70 but I let the car have a few more aggressive accelerations (3x 5k gear changes in 2nd) and I’ve lost maybe 200ml of coolant…

 

call me crazy but would anyone have a reason for this other than the head lifting?

 

ive so far not been impressed with the work that was carried out when the head gasket was done so why would I not suspect the head not being torqued properly or not re torqued after a heat cycle?

 

I don’t really fancy taking the rocker cover off and I’m not even sure if the head bolts are accessible without removing the cams so if anyone has something else I should try first let me know

 

cheers 

Tom

[Breezy_Pete]

24 minutes ago, Mrr4nd411 said:

would anyone have a reason for this other than the head lifting?

I wouldn't. 

25 minutes ago, Mrr4nd411 said:

re torqued after a heat cycle

I think that's been consigned to history. More likely the head needed a skim but didn't get one, at a guess.

[Mrr4nd411]

11 minutes ago, Wino said:

I wouldn't. 

I think that's been consigned to history. More likely the head needed a skim but didn't get one, at a guess.

According to the garage the head was sent off to be skimmed

 

but if it was a warped head surely I would be loosing coolant all the time and not just under high boost conditions? 
 

unless there’s something I’m missing…

Edited 21 September, 2021 by Mrr4nd411

[sepulchrave]

1 hour ago, Mrr4nd411 said:

According to the garage the head was sent off to be skimmed

 

but if it was a warped head surely I would be loosing coolant all the time and not just under high boost conditions? 
 

unless there’s something I’m missing…

 

You're missing something.

 

Head lift is caused by bad bolts, not a warped head.

 

You'll need to get the head gasket redone, the previous standard of the work done is unacceptable.

[Mickmartin]

2 hours ago, Mrr4nd411 said:

 

I don’t really fancy taking the rocker cover off and I’m not even sure if the head bolts are accessible without removing the cams so if anyone has something else I should try first let me know

 

cheers 

Tom

I think this may be your end result bud,   As soon as I read that head gasket had been done and the head had been skimmed alarm bells rang as I haven’t once heard of anyone having this issue in my years owning one of these(that’s baring in mind there’s 2k members over on the Mk2 vrs Facebook page and not came across one)

 

Yep you need to remove a sh*tload of stuff , including the cams to access the head bolts

 

 

Hence why I asked if the garage had mentioned if they had done the  timing chain etc as it would have been wise to as it’s recommended.

 

Strip it down, Check the cylinder head for distortion and have piece of mind someone competent done the job this time.

 

Can send you over the workshop manual if you need it.

[Mrr4nd411]

1 hour ago, Mickmartin said:

Can send you over the workshop manual if you need it.

Thank you and Yes please, that would be very helpful

 

Yeah I think it’s time I accept that it’s the HG, even though I’ve found issues elsewhere it does keep coming back to HG, at this point it’s wondering if I should just replace the engine,

 

the thought crossed my mind about picking up a written off polo blue gt (2015/16 1.4 turbo) and swapping the engine in(and mapping it to 180bhp) the loom would be a PITA but at the end of it I would have a car with the same power that’s more economical and more reliable.

 

if I do all that work to find a crack in a cylinder wall or a warped head I think it might break me. Especially as I fear I’m going to uncover more of this engines secrets the further I dive into it.

 

out of interest how many hours go into changing the HG on this engine?

 

Edited 21 September, 2021 by Mrr4nd411

[sepulchrave]

A job like this is a day to strip and a day to rebuild if you're an enthusiast, you need to get the head properly pressure tested and trued in between and carefully inspect the cylinders for any signs of cracks. In fact before you strip it do a proper compression and leakdown test on each cylinder to help identify any issues. I strongly suspect it's been brutally cooked prior to the rebuild and the previous owner cut corners to just get it saleable.

[Mrr4nd411]

Okey dokey..

 

little update:

compression test and leak down test done today,

 

compression on all 4 cylinders was between 145-150psi.. nice and matchy 

 

leakdown test was below 20% on all 4 cylinders.. again nice and matchy… 

 

Still over heating.. still losing coolant. Still no sign of where coolant is going, noticed it spitting some watery substance from the exhaust when bounced off the 4K soft rev limit, didn’t smell like antifreeze but probably is.

 

at this point I think I’m going to change the engine, I’m sick of this one, I’ll take this engine apart once it’s out the car

[bigjohn]

12 hours ago, Mrr4nd411 said:

Still no sign of where coolant is going, noticed it spitting some watery substance from the exhaust when bounced off the 4K soft rev limit, didn’t smell like antifreeze but probably is.

 

 

The tsi is well known for producing water& vapour out of the exhaust - my CAXA does this sometimes especially when cold but mine doesn't loose coolant.  

 

Have you checked the water pumps (there are two)  as these are a known fail?  I believe this engine has a fairly small water capacity so is rather sensitive to coolant level. Worth checking before you start removing the engine. It has two cooling circuits with the two water pumps & thermostats - designed for rapid warm up to reduce emissions etc.

 

What state is the radiator in - with previous issues it could be partially blocked? When warm is the temperature consistent across the core? Also any staining at the edges where it joins the core - common leak point.

 

I does sound as thought he engine has had a previous major fail though and the way the bores are designed could spell bad news although this would possibly have show up with the compression test.

 

 

Edited 4 October, 2021 by bigjohn