I had some doubts that my temp sensor which feeds the dash is reading right on my Golf MK2 with an ABF in. The coolant gauge reads high after about 30mins of driving, but the fan doesn't run. The temp showed so high last weekend that the light started flashing (I quickly stopped and switched it off) but the fan still wasn't running. I've pulled the plug off the rad fan switch and bridged the connections to test the fan and it works when I do that. I'm using a brand new MK2 8V GTI Radiator which I fitted when I did the conversion a couple of months ago, the thermostat is opening and the radiator feels like it's all getting equally hot. With this in mind I reckon the fault is one of the following: -The engine may actually be overheating (hopefully not , could be the fan switch) -The sensor for the gauge might be faulty -The gauge/wiring might be faulty So to get an idea if the sensor is faulty I took it out and measured the resistance of it at different temperatures by sitting it in a pan of water and heating it, using a thermometer to keep track of the temperature. I got this: Looks to be a good smooth shaped curve, but I can't find any specs to compare the resistance readings to. At least now I can figure out a more definite engine running temp by measuring the resistance, but I'll do that tomorrow when it's light if I get chance. What is the normal running coolant temperature for a ABF? While I was at it I tested the ECU temp sensor too and got this: Do these both look about right? I found the values for the ECU sensor in this thread http://www.seatcupra.net/forums/showthread.php?t=241419 and it seems to match up ok. How do temp sensors tend to fail? Do they go open circuit, give wrong resistance or become intermittent? Is this the way to diagnose temp sensors? The temp gauge works intermittently, and it was intermittent when I had the original engine in too but it never read a high temperature. Has anyone had similar experiences?
Little update: Checked the resistance of the two sensors after driving it today and both readings matched up to make the engine temp 98 degrees, which seems to match up with the temp sensor in the dash because the needle was sat pointing at the next marker up from middle. I left it sat on the drive with the engine running and it seemed to sit at about the same temp, I've noticed the fan appears to work too, it gets to about 100 degrees and the fan switches on to take it back down to about 95 degrees and repeats this over and over fairly happily. But while squeezing hoses I noticed the top rad hose is quite hard. Is 100 degrees ok or is this a bit high?
when driving along i wouldn't expect the gauge to ever move over around half way, but once sat still the temps will rise and fan should cut in to bring em back down again. to work properly the coolant system needs to pressurise as well, so slightly hard hoses are to be expected 98 is a little hot compared to mine though, did you fit a new thermostat when the engine went together? the stock abf stat is actually slightly colder than the mk2 one. another thin to check is if you are using the abf top hose that the thin pipe to the header tank isnt blocked, common issue on the abf as there is a plastic insert in it which is really tiny. though since you have a mk2 golf rad you're probably using the mk2 type thin hose to the top nipple? I'd still check it as the mk2 ones can still clog. when you rev the engine with header cap off there should be a nice stream of coolant and bubbles to the top of the tank also while you're looking check you have a proper mk2 gti radiator, the mk1 golf carb rads are thinner single core type but the proper gti ones are duel core. they are otherwise the same dimensions so will swap straight over, but the cooling performance of these rads is pretty poor as I found out!
Cool, cheers John, thought it seemed hottish but wanted to be sure. It hovers between 95-100 while driving so something must be slightly off. The thermostat was one of the few things that I didn't change (I didn't do the water pump either because the engine only had about 70k on it, though obviously did timing belt and tensioner), so I'll get one from VW and try it, at least for piece of mind. I've had a quick look on Vagcat and found the part no 037 121 113 which is apparently 82C-97C, does this sound right? You're right John, I've got the mk2 style plumbing layout with the small hose by itself from the top corner of the rad to the expansion tank, it's brand new because the original was a bit tatty and it's getting a nice stream of returned coolant which increases if I increase the revs. The twin core vs single core theory is a good one, I never checked, I just fitted the one I got given by euro car parts, which I looked up online using the reg no for my mates mk2 gti 8v, might grab a torch and see if I can tell if it's definitely twin core. This is the rad I got http://www.eurocarparts.com/ecp/c/Volkswagen_Golf_1.8_1990/p/car-parts/car-cooling-parts-and-car-heating/cooling/car-radiator/?203440661&1&18abe07285a4e4aa6c684b4bf948810917a499d9&000261 Cheers Tom
Just took the grille off and checked and it looks to be twin core (I can make out a set of round tubes at the front and a set of tubes at the back). I'll phone VW and see if I can manage to pick up a thermostat after work someday this week and I'll see if that makes any difference. It dawned on me as I stood there in my slippers inspecting my radiator in the pitch black with a torch, that being a classic car enthusiast is a bit odd.... who in their right mind does this, I'm pretty sure my neighbours think I'm mental because I'm always wandering to the shed or car late at night to tinker with something lol
yup thats the one, just a wee bit cooler I would rather have a good 2nd hand VW waterpump than some of the pattern ones you see, can be a bit poor! Did you change the lower thermostat flange for a mk2 golf one? if not fit a new one of those while you're there you'll find the mk2 lower rad hose fits much better for the rad if the fins are about the same thickness of the plastic tanks either end its a double, on mine it was half the thickness and my 16v didnt like it! was just dug out of the pile of spares supplied with my old cabrio and i dint even think to check before i dumped it in there Hehe I can picture that in my head, my neighbours must have thought the same back in the day I used to sit out back of my garage surrounded by wiring. morning! nice day for it eh?
Yeah the core of the radiator is about the same thickness as the plastic end caps so it must be twin core. I think I've got a non-conventional setup of hoses because I started with a 1.6 with the smaller rad, but it works fairly well and isn't pulling/kinking any pipes: I'm using the ABF thermostat flange with the original 1.6 top hose neatly cut down to length as the bottom hose, and the mk3 golf ABF bottom rad hose is now being used as a top hose. I tried to get a thermostat earlier today on my lunch break but apparently the part 037 121 113 is obsolete. I phoned the VW commercial centre 5 mins down the road from me then tried TPS and both said the same thing that it's obsolete. Are non-genuine thermostats ok, are there any particular brands that'd be preferred? I tend to like fitting OEM-level quality stuff if I can. I found this link which mentions a thermostat which is listed for a few other older models and industrial engines into the 2000's part no 056 121 113 A which is apparently 80c-91c, any idea if this is suitable? Might see if VW can get that one if so. http://www.clubgti.com/archive/index.php?t-230483.html
cool so long as it all works no need to worry shame about the stat gone NLA, but I've never had any issues with bits from AVS: http://www.vwspares.co.uk/g3cooling.php the industrial one could work, couple degrees prob wont make too much difference, VW showing it for 24.17+VAT if you want to go that route but I'd go for the AVS one I recon
Cool, cheers john, not sure why I didn't find that on AVS, I'll get one and see if I get chance to do it this weekend. Luckily I live just a 15 min drive from work so it doesn't have chance to get too hot lol
Progress update... (or lack of) Last Saturday afternoon I tested the rad fan thermoswitch in a pan of boiling water and it appeared to be triggering a bit late. It says 95/85 and 102/92, but it only triggered the low speed circuit just as the water got to boiling point. Got a thermoswitch on Monday on my lunch break at work and put it in Monday night. After that, with it sat on my drive with engine running it'd warm up to 95c, fan turned on, temp dropped to just under 90c and the fan turned off again, and this cycle repeated as it idled. Took it out for a mixed drive with a bit of dual carriageway and some town driving, and as before it got to between 95-100c and stayed there regardless of speed. I stopped and let it idle for 5 mins in a car park and it still didn't drop or rise with the fan running. I ordered a thermostat from AVS in the week, it came super fast, and was a Wahler one, the same manufacturer who made the VW one I took out. Strangely it came with two O-rings which were a kinda squared-off u-profile rather than the one 50mm o-ring I was expecting, the larger one looked like it was intended to be fitted around the edge of the thermostat, no idea what the smaller one was meant for? It also said 83c rather than 82c, no bother there. I wasn't entirely sure that it'd seal but I thought it could've been a new improved sealing method, anyway I fitted it and it leaked... Out of desperation of needing a car for Monday morning I re-used the old o-ring and used a bit of instant gasket to help and it appears to have sealed, I'll have keep an eye on it and get a new o-ring Monday then sort it out one evening next week This is the two strange O-rings and the new thermostat This is how I assumed the larger of the two O-rings/seals was supposed to fit the thermostat, but leaked when fitted Before I set off for a test drive and as I filled/bled the cooling system I had it sat running checking for leaks, it got to 95c as before, fan came on, the temp went down to just under 90c and fan switched off, and this cycle repeated so all seemed well at this point. The bottom hose got hot at around 85c as it was warming up so thermostat must be opening at the right temp, out of curiosity later on I also tested old one that I took out and it was opening at about the same temp as my new one. Anyway, I took it out for a drive again tonight and it warmed back up to 95-100c as I drove and stayed there regardless of speed, I headed up some dual carriageway which was 50-60mph and it still wouldn't cool down. Sat it idling on the drive for 5 mins when I got back and it wouldn't drop below 95c with fan running. I checked the temp sensor resistance to check that it wasn't my gauge that was reading wrong and I got 78ohms, so it must've been correct at about 95c idling with the fan on. I'm running out of ideas, tempted to try a bigger radiator now, though it shouldn't need it... I don't think any of the cooling system is blocked, the coolant has been perfectly clean every time I've drained it. I've seen that a Diesel radiator or a A/C model rad is massive and is fairly cheap to buy, but I'm a bit stumped what I'd do for a fan (or fans?), I can't seem to find much on the subject of these radiators and what the fans look like. Might have to get a compression tester so I can rule out headgasket for definite too, though the fluids aren't mixing and I'm not using coolant so this is unlikely. Is there anything in the engine management/electronics side of things that could be making it run a bit hot (fuelling, ignition advance?), surely this is pretty unlikely though? At least I'm getting good at testing things in a pan of hot water on the hob, it's not a difficult skill, but useful none-the-less. Might put it on my CV lol
Interested to see if this gets solved. since i put the ABF in my 1.6 driver i have had readings up to 3/4. I rebuilt the ABF with the following new cooling parts: head gasket set and bolts(obviously) complete water pump thermostat mk2 gti radiator and top hose 2 x 10 inch ebay slimline fans low temp fan switch mk3 heater matrix and hoses (gets rid of the crappy bypass valve) header tank and cap 2 x dash temp sender 1 ecu temp sender (which reads 92degrees on snapon machine.) anyway it would sit about 3/4 up the gauge before the fan cut in, so i bridged fan switch but it made little difference as the thermostat was closing. i replaced the thermostat twice, the latest one was a genuine ABF one (in the mk2 housing) which helped a tiny bit but still runs hot. i have driven it very hard on the road for 5000 miles like this and done a couple of short track sessions at lydden hill in it. the light regularly flashes at me when it touches just over 3/4 then the fan cuts in. i did have a wiring issue when i first got it running where i had accidently swapped the mk3 breather heater plug for the ECU temp plug. for some reason this caused a new Dash temp sensor to explode out the side of the head lol. for me i believe it is either a wiring issue or my clocks have been knocked while they were out? it doesn't try to boil or anything although it does seem quite hot when i lift the bonet.
I think mine might have closed the last thermostat a little after a while with the fan running, the air blowing out the back of the rad fan started to feel cooler after a while with the fan running even though the ends of the rad still felt quite hot, I haven't had chance to check if it still does the same with the new thermostat in. Mine doesn't boil either, my warning light only flashed on one occasion, though I generally only drive 30 mins tops, it's only 15-20 mins to work so it doesn't get chance to get too hot most of the time. The one time it did flash the warning light was when I'd driven just over an hour, but it wasn't boiling over then. I take it that your golf doesn't have an oil temp readout through the MFA because yours started life as a 1.6 like mine? I'm curious what my oil temp will be (and yours for that matter), I'm trying to find a breaker near me that I can get the wiring from to fit the MFA stalk so I can read off oil temp too. I don't have the heater matrix bypass valves in either, I've used the mk3 hoses there too. Like I said, next thing I'll likely try is a bigger rad for how little they cost. I'll be posting up as and when I make progress so I'll let you know if I find the source of the problem.
it could be you have a bit of debris in your rad, flushing pushes it a bit so coolant is clear but then when all reassembled it moves back and clogs again. some one had the same with their carb inlet manifold, they would blast it off the car with a hose and all clear, then when refitted a few miles down the road it clogged again. after 3-4 tries they eventually managed to blast the remains of the coolant channel oring out of the inlet and problem solved! personally I would just buy a new GTI rad anyway, it will be fine so long as the rest of the system is workign right which it should be according to all your tests. but if you wanted to fit a diesel rad then by all means, it wont hurt I would have a word with AVS about the thermostat issue, the seal isnt right it should be a nice fat oring the same as the old one you had. may be worth getting a new thermostat housing though they can warp with age
I got in touch with AVS last week and they popped me the right seal in the post, it came Thursday while I was at work, so I sorted that last Saturday. Can't fault them for sorting it, had no bother from them when I called. I've had the coolant out quite a few times now and there's not been any bits in it when it's come out, the coolant has looked as good as when it went in every time. I gave the engine a good flush-through before I first filled it and it was running out clear then. The rad is a brand new GTI one from Euro Car Parts, my original was a very tired 1.6 small rad. I haven't tried flushing rad out with hose since fitting it so I might try it. I recently discovered the measuring blocks function in VCDS lite while scanning a 2003ish beetle that a mate of mine has recently bought, so I thought I'd check what the ECU is reading the engine temp as while it is running, but it gives an error message along the lines of: "controller not found". I can read the measuring blocks and fault codes with the engine off, ign on ok, but it gives the error message if I try it with the engine on? Can the ABF ECU be read when it is running? The measuring blocks function seemed to work fine n the beetle while it was running. Would be nice to confirm that the temp sensor/gauge are definitely right and aren't playing games... Really got me scratching my head, everything seems to be ok other than the temp gauge reading high even though it's heading towards winter. It drives fine, though I'm not sure if it's using a little too much fuel, I think I'm getting 280-300 miles to about 45 litres of fuel. I also have a suspicion that my relay 30 is past its best, I have had a misfire on a couple of occasions, the last time it happened I pulled the relay cover off as I was driving and flicked the relays one-by one lol , when I flicked relay 30 the misfire stopped, though I don't think this could have any influence on overheating, even when it drives fine now? I'm yet to get a compression tester to try to rule out head issues.
Mine was a new gti rad from ebay. I drove mine hard most of the time. did a top speed run on the way to lydden hill i wont post numbers, but it was flashing the whole time. then after 2 x 15min sessions of flat out tyre melting around the track, it was almost at the top of the gauge flashing. opened the bonet, was very hot but still not boiling. anyway when mine comes back out of hibernation it will hopefully be on Megasquirt so we will see what MSDroid and shadowdash report.
yes the ecu should have no problems communicating with vagcom while running, has it got an immobiliser? the immob box may be playing up or it could be related to the 30 relay issue so get that sorted sooner rather than later its cheap from vw anyway. is your rad a double cored one, it should be as thick as the end caps mine is a hella GTI rad and is tip top
Slight progress on VCDS issue, I found something on a T4 forum where someone else couldn't connect with the engine on, they got round it by disconnecting the alternator. I just went out on my lunch and tried it with the exciter wire disconnected so that the alternator was disabled. It connected with the engine running with the exciter wire unplugged, I plugged it back in and it killed the VCDS connection and it gave the "controller not found" error again. I'm not quite sure what to make of it, could it be that the alternator pushes the voltage too high for my cheapo lead (I measured 13.4 V at the OBD plug with engine running, not that high?), or could the alternator be creating some sort of interference? I didn't think to try turning everything on (lights, heated screen, heater, etc) while the engine was running to see what the voltage is and try connecting then at what I hope could be a lower voltage, might try it later. I'll get hold of a relay 30 tomorrow if I can, see if that has any effect to anything. It's a double core rad, can't remember what the brand was but I remember it said made in Germany, it was one from Euro Car Parts.
Right, time to close this off, I know you'll have been on the edge of your seats in anticipation!!!! (is anyone's sarcasm sense tingling? lol) I don't want to be one of those people who don't post up what fixed it in the end. I ended up buying a MK2 Golf GTD radiator brand new from Andrew Page sometime around the start of December, think it was about 40 so not too bad. It seemed to run cooler when I fitted it, but I didn't want to speak too soon because it was really cold so that'd help the cooling anyway. Since then, I've driven from Sheffield to Scotland in April when it was fairly warm and I've driven in the hot weather recently and it seems that the GTD radiator has sorted it. I've also recently wired up the oil temp sensor up to my clocks and got an MFA stalk so I can keep an eye on oil temp too, it usually sits mid 80's to 90c and a little more when I give it some stick, so I'm happy with that. Strangely my MFA temp reading varies a few degrees if I switch the headlights or blower on? I got a new relay 30 and it's never misfired again so that was that, though I never managed to figure out why VCDS doesn't work on mine with the engine on, no biggie though, I'm sure I'll figure that out someday. Cheers for the help along the way.
On the edge of my seat boiling! This whole thread is identical to the issues I have. So for the purposes of adding to the conclusion, yes there was one person on the edge of his seat, no sarcasm here! I dont have a heater matrix, I assume the total water volume may have a part to play. I had also bypassed my oil cooler/heater and it hadnt helped. Since revisiting the oil cooler hosing and replacing it, the temps improved. I also had VAG COM and it reports the coolant temps at 102c. Whether the sensors are correct or not is to be determined. Yes, when I sit at the lights, my temp gauge can max to 3/4, yes once I get moving it settles down below 1/2 way. My findings for over heat often leads to a leak somewhere and like RJ said, its about pressure, so if there's a pressure drop the system can boil over. My conclusions arise from now having a cold winter to test in and while the temp guage now sits well below the 1/2 mark it shifts my focus away from the radiator. I will by choice use a colder thermostat in future, the system in the sub-tropics with 30c+ temps most the year round is stressful. I also believe that once I replace the heater matrix that additional volume of coolant will help. I also KNOW that without backfilling the engine block and radiatior I will create an air lock, which then shoots temps all the way to 3/4 on the guages. Got an oil filter and oil in the car waiting, but I want the sump off and check the oil pickup. Then I'll give it one more flush and report back. Will be swapping the heater matrix in the coming months. Thanks for posting! Things Ive done... New Water pump New thermostat Radiator and engine flush New Oil cooler hosing New coolant reservoir 50 ohm resistor on oil temps to match actual to dash.
with the oil moving a little when lights on, check the earth to your head make sure its nice and clean
