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Model specific boards => Golf mk3 => Topic started by: MK3 Menace on 26 July 2012, 13:01

Title: Car getting hot after rebuilding front end...
Post by: MK3 Menace on 26 July 2012, 13:01
Hi all,

Like i said in another thread I had a small shunt that involved rebuilding the front end. Replaced slam panel, crash bar and fitted a Vento front end.

I thought I bled the system ok but took it for a small drive last night (about 5miles) and the temperature rose to 100. Its normally solid as a rock on 90.

I let it cool and popped the expansion tank and it coolant promptly spilt out the top.

So I went with the procedure I was advised and ran it without the cap on and fans on full to try and bleed to system some more.

The car did spit a few bubbles out and water did tend to rise high and low in the header tank.

I switched it off after a while as the water looked to be boiling although the gauge consistently read 90 and i was worried about the engine cooking.

The fan never kicked in at all and the fan motor felt cold.

Top pipe on rad was warm but bottom was not so much.

So my conclusion is that the thermostat might of failed or I have a blockage somewhere.

I am going to removed both pipes off the radiator tonight and run a hose through as my mate suggested and see if there are any blockages.

If not, do you think it was just a case of me not bleeding the system properly?

I really don't want to have to replace the thermostat or water pump unless I have to as I know the location is an arse.

If it is a fan of the fan not kicking it, is it worth me bridging the connection? How easy to do?

Also, I have the blue header tank cap so I think that should be ok.

Any advice or ideas appreciated.

Thanks,
Dan
Title: Re: Car getting hot after rebuilding front end...
Post by: Gash on 26 July 2012, 13:43
If its over heating it could be a case of that you didnt put enough coolant in there to begin with.
if you just used water instead of a mix then this would also cause it to heat up more (although not loads)

strange that the fan didnt kick in though, but have you got a single or twin speed? if its sitting at 90 i may not kick in until its been sitting at 90 for a while.
Title: Re: Car getting hot after rebuilding front end...
Post by: Gti_Jamo on 26 July 2012, 13:53
Chances are its the thermostat stuck shut or not opening fully. Common failure. They are not too bad to change. Few bolts to remove steering pump out the way and you have good access.
Title: Re: Car getting hot after rebuilding front end...
Post by: MK3 Menace on 26 July 2012, 14:15
I am starting to think I may have been a bit stingy with the coolant. I am going to drain it all off later and start again.

It has two fans down there connected off each other via a belt but didn't know if one was for Air Con or something.

I'll try again with coolant and then will tackle the thermostat if its not kicking the fans in still.

Left the car at 90 for a good 10 minutes I reckon and no fan...
Title: Re: Car getting hot after rebuilding front end...
Post by: VR6_Wherry on 26 July 2012, 14:28
have you ran the heaters on full in the car too? Try that as well.
Title: Re: Car getting hot after rebuilding front end...
Post by: MK3 Menace on 26 July 2012, 14:30
Yeah had the heaters on full when I had to cap off last night to see if i could extract any air out of the system.

I think to be honest thats what helped the car stay on 90 while stationary.
Title: Re: Car getting hot after rebuilding front end...
Post by: Gavv8 on 26 July 2012, 19:32
I am starting to think I may have been a bit stingy with the coolant. I am going to drain it all off later and start again.

It has two fans down there connected off each other via a belt but didn't know if one was for Air Con or something.

I'll try again with coolant and then will tackle the thermostat if its not kicking the fans in still.

Left the car at 90 for a good 10 minutes I reckon and no fan...
That doesn't sound right..
Title: Re: Car getting hot after rebuilding front end...
Post by: Deano2711 on 26 July 2012, 19:37
I had a faulty temp sender which meant mine was reading 90 on the guage when the car was overheating. This could explain that and the fan not kicking in. Cost me £8.75 from GSF and thirty seconds to fit.
Title: Re: Car getting hot after rebuilding front end...
Post by: MK3 Menace on 26 July 2012, 21:24
I am starting to think I may have been a bit stingy with the coolant. I am going to drain it all off later and start again.

It has two fans down there connected off each other via a belt but didn't know if one was for Air Con or something.

I'll try again with coolant and then will tackle the thermostat if its not kicking the fans in still.

Left the car at 90 for a good 10 minutes I reckon and no fan...
That doesn't sound right..

Under the slam panel are two fans side by side, they have a small belt that drives one from the one with the motor. I can show you a pic if you like as I got the old slam panel I took off to hand...
Title: Re: Car getting hot after rebuilding front end...
Post by: MK3 Menace on 26 July 2012, 21:25
I had a faulty temp sender which meant mine was reading 90 on the guage when the car was overheating. This could explain that and the fan not kicking in. Cost me £8.75 from GSF and thirty seconds to fit.

Where does temp sender locate as it could of been something that was damaged or I missed when putting it all back together...
Title: Re: Car getting hot after rebuilding front end...
Post by: Gavv8 on 26 July 2012, 21:26
I am starting to think I may have been a bit stingy with the coolant. I am going to drain it all off later and start again.

It has two fans down there connected off each other via a belt but didn't know if one was for Air Con or something.

I'll try again with coolant and then will tackle the thermostat if its not kicking the fans in still.

Left the car at 90 for a good 10 minutes I reckon and no fan...
That doesn't sound right..

Under the slam panel are two fans side by side, they have a small belt that drives one from the one with the motor. I can show you a pic if you like as I got the old slam panel I took off to hand...
Yes please, i thought twin fan rads had two seperate motors.
Title: Re: Car getting hot after rebuilding front end...
Post by: MK3 Menace on 26 July 2012, 21:38
Bare with me as I'm trying to do it on the iPhone...

http://s259.photobucket.com/albums/hh289/flyingtoilet/?action-view¤t=ec928b94.jpg&evt=user_media_share

http://s259.photobucket.com/albums/hh289/flyingtoilet/?action-view¤t=1764a8d9.jpg&evt=user_media_share

Hope that works and you see what I mean...
Title: Re: Car getting hot after rebuilding front end...
Post by: Gavv8 on 26 July 2012, 21:40
Bare with me as I'm trying to do it on the iPhone...

http://s259.photobucket.com/albums/hh289/flyingtoilet/?action-view¤t=ec928b94.jpg&evt=user_media_share

http://s259.photobucket.com/albums/hh289/flyingtoilet/?action-view¤t=1764a8d9.jpg&evt=user_media_share

Hope that works and you see what I mean...
Your album is set to private, can't view the pics.
Title: Re: Car getting hot after rebuilding front end...
Post by: MK3 Menace on 26 July 2012, 21:43
Ok give me 5 and I'll host them elsewhere...
Title: Re: Car getting hot after rebuilding front end...
Post by: MK3 Menace on 26 July 2012, 21:44
(http://i259.photobucket.com/albums/hh289/flyingtoilet/1764a8d9.jpg)

(http://i259.photobucket.com/albums/hh289/flyingtoilet/ec928b94.jpg)
Title: Re: Car getting hot after rebuilding front end...
Post by: MK3 Menace on 26 July 2012, 21:45
That worked, see what I mean? 1 motor and belt driven on the front behind the grille....
Title: Re: Car getting hot after rebuilding front end...
Post by: trog_nfs on 26 July 2012, 21:47
air con cars have twin fans joined together by a belt. They are both switched on when aircon is activated
Title: Re: Car getting hot after rebuilding front end...
Post by: MK3 Menace on 26 July 2012, 21:48
Ah got you, so belted one is air-con, motored one if for engine.
Title: Re: Car getting hot after rebuilding front end...
Post by: Gavv8 on 26 July 2012, 21:48
Well i learned something new today.. :embarassed:
Title: Re: Car getting hot after rebuilding front end...
Post by: trog_nfs on 26 July 2012, 21:58
the belted fan is just a slave off the other. If the motored one is running, so is the belted one.
Title: Re: Car getting hot after rebuilding front end...
Post by: Deano2711 on 26 July 2012, 22:09
Temp sender is locater where the top hose meets the block....the top hose goes to a large block and the temp sender sits at the top. When the engine is cool remove the plug and then push down on the temp sender and pull out the retaining clip and its out. My temp sender was yellow but think there are a couple of colours. Worth changing to ensure the temp guage is giving an accurate reading.
Title: Re: Car getting hot after rebuilding front end...
Post by: 67buggers on 27 July 2012, 06:26
Have you checked your fan is wirking ok? Could be your fan switch sensor.... Not expensive and easy to swap. Mine wouldnt kick in when it got to temp and that wad the cause alOng with the thermostat.
Title: Re: Car getting hot after rebuilding front end...
Post by: MK3 Menace on 27 July 2012, 12:42
I am going to do this tomorrow now as work has got in the way.

I am going to do the following, if you guys think I need to do things differently let me know.

1. Drain and refill using more coolant.
2. Bleed system with cap off and fans on full.

If that does not cure it I will.
1. Replace temp sender.
2. Check fan wiring.
3. Replace thermostat.
4. Check water pump out.

Dan
Title: Re: Car getting hot after rebuilding front end...
Post by: Gti_Jamo on 27 July 2012, 18:09
If your draining the coolant you'd be better doing the thermostat at the same time as will save you draining it twice if it turns out to be the problem. I'd put money on it being the thermostat.