Have you actually replaced the thermostat? In the first post you say But I think you mean that you replaced the two temperature sensors, black one for the gauge, and the blue one being for the ECU, I guess. The thermostat is in the water-pump housing. I'm not saying it definitely is the problem, but it may be that it is not opening widely enough, hence the higher temperatures than expected? Another possible explanation for your gauge readings is that you have a two-speed radiator fan, but only the higher speed is working. This might be due to a problem with the fan itself, or the thermoswitch on the radiator. If it is a dual speed fan, the thermoswitch will have three pins. I can't remember the wire colours just now, but to test the low speed, you just need to link the middle pin of the thermoswitch's loom connector to each of the outer pins in turn. One of them should bring the fan on at the low speed.
some good tips there, the slow speed is red/white and fast red/black, also have a read thru here: http://www.clubgti.com/showthread.php?145091
Thanks EZ Pete and Johnny, I have checked over the car today, changed the oil and gone over the cooling system again. The only parts I haven't changed are the red sender in the housing at the front of the engine, the radiator and the water pump. I'm not sure about the pump housing thermostat, that is new to me. I couldn't see it but will have another look soon. Looking over my radiator I noticed this [/IMG] Not sure if it would effect anything but sure it's not good anyway. Wonder if my radiator needs replacing? That and the red sender just to be sure.
bit of localised damage like that shouldnt affect it too much, but you may want to inspect it further after removing the grille.
The radiator damage looks irrelevant to me. In my experience, replacing a genuine old radiator with an aftermarket new one can be a step backwards. A good flush through into all pipe connections, off the car, with a hosepipe turned up to '11', should sort out any waterway cloggage. Use the hosepipe with a bit less pressure to thoroughly squirt away any dirt and debris from amongst the air fins while you're at it. Here's some pictures of the thermostat housing (and thermostat within!). Access is good if you don't have power steering, and a bit rubbish if you do. http://forums.vwvortex.com/showthread.php?5450461-Epic-thermostat-housing-failure General wisdom is that that plastic housing should also be replaced if/when you do replace the thermostat.
I did think that there wasnt a problem with it as nothing comes out but thought I would check with the gurus. I have a genuine radiator stored at my father inlaws place in the UK as the one on my old car developed a leak, so was due to overhaul the cooling system with it and pipes etc up until the point where the car was written off by a numpty on the M25! I will fit it one day but not much point. I had all the pipes, radiator, and expansion tank off the car so flushed them all through and checked them before refitting with new clamps, flanges, senders and fluid. The one I missed was the thermostat Thanks for the link, now I know what I'm looking for I should be able to find it. unfortunately i do have the power steering model so it will be a pain and prob the reason I missed the housing when looking. I have now placed the order with VW heritage and it will be posted today apparantly. fingers crossed it solves the issue. Great advice as always guys thanks you Simon
have you checked the timing yet? free thing to check anyway and could explain the overheating and slow performance
Not yet, I have not had chance due to work commitments. I hope to have a look next week if I get chance. I would not be surprised if its a out as I have no idea when or if its been checked previously
Hi, I've been looking at the thermostat fitting and I have power steering so will a damn sight harder to replace it. Can I remove the power steering bracket first then the thermostat, or do I have to remove the alternator as well? Seems a proper PITA! Hopefully it's just the bracket at the front I can remove I have ordered a timing gun so hopefully that arrives next week and I can check the timing also.
Depends how the belts are configured, but you should be able to just swing the alternator up once the belt is off. You're right about it being a PITA when I had to do mine the pivot bolt was corroded into the upper PAS alloy bracket so I had to take the upper and lower off as it was frozen in position plus get some replacements. There's some advice/discussion in here about getting it undone and set up again. http://www.clubgti.com/showthread.php?272703-How-to-take-out-waterpump-belt
Thanks finite, I am hoping I can remove the alternator belt, undo the bolts and pivot the bracket out the way and get to the flange. It's not too rusty actually which I'm amazed by, that's not to say I'm not going to liberal with the plus gas! I hope I won't be eating my words at this point hey. I'll be upgrading to the mk3 system when I can but for now I'll fight with this system and change the thermostat so at least it's done, sort the timing out, do a compression test and then maybe after that's all done, the car should running right and I can focus on the brakes, suspension and then interior. Thanks again
I think my problem was a bit of a one off it's not happened again in just as long time. I'm not sure what the Mk3 setup is like for stat changes, but ideally I'd like a remote stat in the hose after reading about them. I've yet to see if it's feasible.
the mk3 setup is a little easier for stat changes 4 bolts and the pas pump plus bracket comes off and you can just swing it out the way, no silly threaded adjuster thing either just a nice toothed wheel same as what the mk2 alternator has so less likely to have stuck bolts or whatever
So, I finally got round to checking the timing this morning. Well actually I checked it last night to discover that the timing was indeed out; the diamond on the flywheel was not in line with the mark on the bellhousing to the right of the mark as you look at it. The reason why I checked last night but could not adjust it was that my dizzy was stuck solid, no shifting it!! So this morning I set out adjusting the timing by persuading the dizzy (gently) with a length of timber and wooden mallet. Now the timing marks line up spot-on. Went for a drive and as I pulled out of the garage, the exhaust was spewing fluid galore and then white smoke. Hmm! Could just be a symptom of the system needing to settle down I hope. Anyway went for a drive, did a couple of high rev second grinds down a straight road and checked the exhaust, no white smoke, no fluids, great. Temp gauge told a different story, she got really hot and the fan had to kick in. So I disconnected the battery for 2 mins, reconnected, started the engine gave 3 revs over 3000 RPM and went for a drive. Put the heater max heat, then turned it down after a whole (wwwwaaaaarrrrrrmmmm!!) and now the temps stay in the centre just about touching the second line on the gauge, but remaining slightly to the left of it. Runs great and the stumbling misfire seems to have gone as well. Will do a good hours drive later so get to see how she is then. Thanks for the hep guys
So I finally got round to doing the compression test and it came out as follows. Cylinder 1 - 190psi Cylinder 2 - 190psi Cylinder 3 - 165psi Cylinder 4 - 190psi Seems the third cylinder might be under compression which sucks. Plus I hear a tapping from the back of the engine so I think the manifold gasket might be blowing, as there is also oil seepage from the bolts onto the head. When she is running there is fluid coming from the exhaust as well. Altogether this prob doesn't look good for the engine does it? Will try and get the head off soon as I can and get all the gaskets changed etc but getting married in a month and that takes president apparently!
That's a bit of a blow. I have some problems with the coolant system on mine which I'm hoping is just some kind of intermittent blockage from the heater bypass valves or similar, but I guess I should do a compression test too and find out the awful truth.
Well good luck mate, I really hope it is a blockage that can be sorted easily for you and nothing serious. I'm gutted about the low compression, was hoping it to be an easy fix when I had to adjust the timing but it looks like I need to rebuild. The power from the engine is really starting to reduce, there doesn't seem like there is any pull from low revs. As soon as I can I will pull the head off and check the gaskets etc, but think the worst, hope for the best. Thinking about the possibility of having to rebuild the motor plus I'm hoping on keeping this car as OEM as poss, I am looking to source some GTi pistons and adding them with a Newman fast road cam to the 8v head (ported and flowed), intake plenum, TSR four branch manifold and full jetex exhaust I have sitting in the garage to make a decent GTi for the rebuild as this car is my daily, but no harm in upping the power I know there is the 2ltr conversion and the ABF but I don't want to do that as everyone does and good gains can be got from a well set up 1800 8v or at least enough for me with this car anyway (I have a stripped out 1979 RX7SA with over 200Bhp at the rear wheels that covers my hooning requirements) plus I have most of the parts sitting there as I wanted to do this for ages hey. Of course will determine on what I find when I strip the head off and take a look. Good luck with yours dude Jonsie
Hey Jonsie, I just read something on another forum that might be relevant here. Post #3 here seems to be suggesting that the coolant will be hotter when you use this Evans stuff. It seems like it may be the answer to your observed difference in the temperature gauge reading since changing to this stuff.
INteresting read thanks for that mate. I have been wondering about this as the temperature goes up just past vertical and stays there, no problems as if its just reading a little higher hey, then if stopeed and it has been super hot this year, the temps climb a little, then settle down again once I'm moving. The link you posted seems to suggest that it will run hotter and to be honest, it makes sense hey. I thought this Evans stuff would be good for the engine but I'm not sure now. I'm due to check over my engine again with the possibility of a rebuild real soon and thinking of going back to 50:50 G12 coolant as I'm not sure I like the idea of the engine working harder to keep cool. Thanks again
So I have been away for a month with work and getting married, so checked over the engine a little before starting her up to go get some food and saw a pool of oil had collected below the coolant flange in the head at the front of the engine. Looking at the joint between the head and block I see that there is a leak which is next to the cylinder that has the reduced compression, so I'm wondering if the gasket needs changing and that's the reason for the drop in compression! [/IMG] And yes I keep wiping it away and checking and it comes back. Then I spotted this on the red sender in the flange[/IMG] . Good job it isn't right next to the connector so I can rewrite it. Oh no wait it is. So I need to replace the lead now, good job I have a spare jetta for parts perhaps this didn't help the whole mis reading of the temperatures?
