Coolant troubles

[Skodamk1vrs]

Hi all first post on here I have owned my beloved mk1 octavia vrs for around 3years now lots of modications...recently the coolant flange housing gave up while I was driving it started over heating...so I replaced the flange with a new 1 as well as all new seals and new temp senser put it all on...vac bled the system new coolant started engine blowers on full hot setting and let it run for around 20mins the temp climbed to 3quarters up the temp gauge so over half way...plus no hot air thew the blowers at all only cold and no fans cut in iver..need help thankyou

[kentphil1]

Firstly, welcome to Briskoda.

 

Do your fans turn freely?, siezing is not unheard of with the fans.

 

Also, the thermo switch on the radiator may be faulty, there was a test procedure that I posted on here about 2-3 months ago on here via a youtube vid, I'll see if I can find it again.

 

The lack of hot air sounds like either you have the mother of all airlocks, or the thermostat is goosed.

Edited 4 December, 2016 by kentphil1

[kentphil1]

As promised -

 

I take it none of your fan fuses are blown?.

[Skodamk1vrs]

Hi kentphil.. thankyou for the welcome yes fans turn freely so not seized haven't done the fan switch test yet but will thanx..and ime really hoping it's not headgasket ive got no other signs of this so fingers crossed gonna try bleeding threw the correct bleed valves..will this be worth doing pal

[Skodamk1vrs]

I had to drive 3miles with car absolutely red hot over heated as well that's why I have the bad feeling about it

[kentphil1]

You appear to have 2 separate faults on the surface of it here,

 

1 - the car is running hot, which I am thinking that you have a jammed thermostat there, 

 

2 - you appear to have no cooling action taking place once the car starts to run hot - you need to do some basic electrical tests detailed in the vid to see what is and isn't working.

 

Do you have access to get a combustion gas or "sniffer" check done on the cooling system at all if you suspect a headgasket?

[Leeboy]

Do you know when the water pump was last done? Did you have a look at what state the impellers were in when you had the flange off if you removed the thermostat too? Do the radiator top and bottom hoses get hot also?

[kentphil1]

If I am correct, the OP is referring to the flange at the other end of the head that the coolant sensor sits in?, perhaps Skodamk1vrs could confirm that or let us know which flange was changed if I am wrong in my assuption?.

 

Water pump is a possible cause, when the car is running with the reservoir cap off, if you get someone to hold the revs at a fast idle up to about 2000 rpm, do you see a constant stream of coolant returning to the bottle via the small bore pipe in the top of the reservoir housing?.

Edited 4 December, 2016 by kentphil1

[Skodamk1vrs]

Thankyou for replys guys..I changed the flange wich the coolant temp sits in also changed this...dont know when water pump was last changed..I may be able to get a sniffer test at work..I work for Citroën but guys in workshop are not clued up on highly modified cars..I've just spent thousands on this machine that's why ime trying to solve this one myself ime running out of money fast hahaha. .The bloody thermostat is a pig to get to as well having to remove alternater and so on..but gotta be done I suppose..are u thinking head gasket tho guys or not?? All was well before this flange gave way ime not loosing coolant now iver..just car getting really hot no fans and no hot air...even when head gasket goes I would still get holt air?? I've had one go on another moter I had and I still got hot air threw the vents

[kentphil1]

Thermostat is not the easiest to get to, but can be done with a 1/4 drive socket set and a selection of wobble bar extensions without removing the alternator. Must admit I would not be leaning towards head gasket without doing more tests. How heavily modified is your car, stage 1, 2 or higher?

 

How many miles have you done in the car since you've had it, as pumps are changed with the cambelt usually, as they only go about 60000 ish before starting to play up. It might guide us to a rough idea of how old the pump actually is.

 

Carry out some of the checks we have highlighted as possible causes in the above posts, and post back the results so we can help you better.

[Leeboy]

As Kentphil says, you can get to the thermostat without removing the alternator. When I last dismantled mine, I did though remove the inlet manifold which is about a 15 minute job including disconnecting wiring, fuel rail and throttle body. Thereafter removing the flange is fairly easy if you disconnect the wiring (suggest disconnect the battery first).

With thermostat out you can see the water pump condition like so

[Skodamk1vrs]

Hi guys sorry for late reply your info is invaluable...rite so car is stage 2 btw.rolling roaded. At 301hp.so sniffer test done no bad signes so ime grateful for that..I re bled the system again using the vac bleeder again..and ran the engine up the car stayed at normal temperature on idle but when I kept on the throttle on idle it would climb quite high and when coming off throttle it would start to retention to normal..I was switching from feet to face on the blowers in the car and suddenly it started blowing hot air!!! Great!!! Only for it to then suddenly turn cold again I was not happy coz I fort I had cracked it what could it possibly be??..still gotdo fan check and look at water pump condition and thermostat all will be completed tomorrow and I will update you guys...Thank you for all your advice

[Skodamk1vrs]

Also all relevant pipes are hot rad pipes ect ect..

[Skodamk1vrs]

Also all relevant pipes are hot rad pipes ect ect..

[Liverpool-Lad]

So how long have you had the car & when was the pump last done?  Probably this if the thermostat and CTS have been chanegd with genuine items.

 

When was the cambelt last done also?

[Saints92]

When you turn the AC on, does it blow hotter?

[Skodamk1vrs]

Rite so new thermostat new temp sensor new coolant housing new fan switch  all fitted today will rin up the engine tomorrow and update this post...and no ac on it doesn't blow hotter

[Skodamk1vrs]

Ran the engine up today with all new parts on and still no cooling fan came on even when car started to get hot no fan kicked in...still got no hot air threw vents wh car started overheat nearly where else do I go help please!! Waterpump maybe????

[Liverpool-Lad]

You can monitor the coolant temperature if you get a cheap ODB2 bluetooth reader and torque application on your phone.

 

When was the waterpump last done?  It suggests its probably this.  I would be very careful driving it until its done.

 

When was the cambelt last done?

[kentphil1]

Do you see a constant stream of coolant returning into the expansion tank if you get someone to hold the revs at 1500 - 2000ish?.

 

If the flow is weak or inconsistent, then the waterpump impeller is definitely in question. The impeller is composite material on a metal shaft, which means it can degrade and not rotate with the central shaft. Most people have the pump changed at the same time as the belt which is changed at 60000 or 4 years according to the latest Skoda info from my local dealer. If you have owned it for circa 3 years, you may be unlucky and the pump is failing a little early.

 

Does your radiator exhibit any cold areas across it's surface at all?.

 

I must admit I am puzzled how this could spring up after changing the initial flange on the head. Was the flange mating surface on the head clear of any obstructions or bits of debris from the original flange?. At times like this, once I have done my basic diagnosis checks, I normally methodically recheck my steps just to be sure I have not "screwed the pooch" myself by my actions.

 

As regards the fan, did you check the fans as shown in the vid I posted earlier?, as there is a relay unit under the battery that controls the fans as well as the thermo switch. Do your fans run all the time when you switch the climatronic unit to auto?. The fan also has an inbuilt resistor to allow the fan to run at low and high speed, which can fail and only allow the fan to run at low speed.

 

There is a well documented how to on VW Vortex of how to bypass the inbuilt resistor for an external unit, let me know if you need it and I'll try to find it for you, but check out your system as per the video first before you jump into that scenario.

 

Edit, just had a thought on this, when the car has been run and left to cool for half an hour or so, when you crack the coolant cap, is there a large amount of pressure released?.

Edited 10 December, 2016 by kentphil1

[Liverpool-Lad]

Lemforder probably which are likely to be OE

 

http://www.vwspares.co.uk/product_info.php?products_id=3380

[kentphil1]

Lemforder probably which are likely to be OE

 

http://www.vwspares.co.uk/product_info.php?products_id=3380

Wrong thread :giggle:

[Liverpool-Lad]

Shh!

[Skodamk1vrs]

checks done as per the same as the vid u posted Kentphil on the fan it runs this way so fort a new fan switch would do the trick

.but car still getting really hot without fan coming on at all..and even with any setting on my blowers I get no fans at all

[Skodamk1vrs]

Plus no hot air threw blowers even after all the new parts..starting to upset me now argghh