kmaccsy

Hi again, just a quick update. Had my mechanic replace the thermostat yesterday morning and its been perfect since, took the car for a spin but as its so cold it was hard to get the thermostat to open. Revved the engine while it was in park and within a few minutes the radiator was getting warm, job done! Just have to have a look at the torque converter issue, it may not be 'economically viable' to get it replaced or reconditioned so am contemplating just driving the car until it fails or I get a new car, whichever happens first! Thanks again for your help, have to say I've learned a lot about automatic gearboxes over the last few days

Thanks for the offer, would definitely take you up on it if I were closer! As you said, just need an experienced mechanic to rule out the chassis. So if the judder disappears after the overheating issue is resolved but the surge remains then I can safely assume the gearbox is on its last legs? One observation, when the engine was warm the judder was occurring roughly around the same time as the surge was when the engine was cold. Maybe just symptoms of the suspected clutch slip at different temps? Also a little video of the instrument panel taken on the run I mentioned going up the hill, juddering starts about 20 secs in. Not the most stable of vids but it gets the idea across! Hard to make out the engine temp needle but you can just about make out it starting to move off 90 at the end of the vid

Disregard my previous post, think I've found the problem, radiator is completely cold after a 40 min drive, pipe on top by passenger side is very hot, pipe underneath on driver side is cold. Took it out for a run there after my last post, there's a steep hill about 30 seconds from my house. Engine was cold, took it up the hill at speeds between 60 - 80 kph, no judder but plenty of engine surging, over-revving by about 200 rpm then coming back to normal. Surging most noticeable when keeping the car at a steady 80kph with the gradient varying up the hill. Drove until the engine was warm, turned around, came back home and went up the exact same hill at the same speeds, lots of juddering and not as much surging. Juddering got bad enough to cause the engine temp needle to start climbing above 90. So the juddering happens when warm but NOT when cold, disregard what I said above. In a microcosm, this is what beens happening to me on longer journeys. When I came home I popped the bonnet and the radiator was completely cold. Expansion tank was very hot, coolant overflowed when I took off the lid. So I think this explains the overheat, the judder was occurring before the overheat so not fully sure if the 2 are related? Time for the rad and cooling system to be examined! Will have a look at the fuses tomorrow, no aircon fitted in the car. When I change gear without lifting the vibration disappears and the engine revs away as expected. Still potentially something mechanical rather than fluid/hydraulic related? Thanks again for the help!

The fans aren't running when the engine overheats, I've never heard the fan running after the igÍnition is switched off on this car. Will add testing the coolant to the list of things to check! There is coolant in the car since last Sunday, for about 3/4 months before that I had been using water in the coolant system without issue. Would the water/coolant discolour if gases were getting into it? Will have a chat with a few more mechanics about testing pressures in the box, so far I have only the one guy whose experience with automatic gearboxes is limited. The judder occurs when the engine is both cold and warmed up. The judder has been happening long before the car started to overheat. To be honest it's been there so long (about 7/8 months, mild initially) I'm beginning to wonder if I've permanently damaged either the gearbox or the torque converter, assuming one of them is the culprit! Could a failing torque converter cause judder initially for a few months and then cause both overheating and juddering?To throw another possibility out there, my house mate reckons there could be a blocked pipe in the radiator? So many possibilities, dunno where to start! Really appreciate your help on this, as you said it's a process of elimination. Edit - just to say the abs controller was serviced by a different mechanic during the summer. I brought it to him initially to have the handbrake adjusted as it was a fail in the NCT. While he was doing that he noticed the abs was acting up - not sure exactly what he spotted and how he spotted it - but said it was ok again after. I only mention this as a sticking brake caliper could be responsible for the judder, though it doesn't account for the overheating. Could still be 2 seperate issues, my head is wrecked...

Thermostat will be looked at but there is coolant returning to the expansion tank. Tracking and wheel balancing was done when I got four new tires in September and the judder was still the same after. Will have a look here about the surge problem. Thanks!

It's one more thing to look at but there's coolant returning to the expansion tank so wouldn't this mean the thermostat is working ok?

Ok so I checked for water in the oil on the dipstick and its just oil there, no sign of water. No mayonaise on the inside of the oil filler cap. I saw the old gearbox oil and it wasn't burnt looking or smelling, it did have a greyish kind of colour to it. My mechanic mate said the oil had a gritty texture to it but as he didn't see any shavings or other swarf he said it was ok. The car was on the lift a few weeks ago to have a look at the dogbone mount, there was no excessive movement in it when they took it off to have a look. The rubber looked good, no signs of cracks, softness or any kind of perishing. Will get him to put the car on the lift again and investigate the driveshafts as well as checking for movement in the wheels, exhaust mounts and bushes.

Thanks for the reply. No white smoke from the engine and no oil in the coolant tank (no discolouration of either water or coolant). Will check for water in oil on dipstick and mayonaise on the filler cap in the morning. I think he said there was a small leak from the cv boot, I'm hoping it was nothing serious but will ask further if the boot was off the joint and exposed (could a cv joint cause the juddering I've described?). Also I have this post up on another site and one reply there says the gearbox is dying...eek!

Hi guys, hoping someone here can give me some help with my car. It’s a diesel ‘03 Skoda Octavia Ambiente Estate, 1.9 TDI, automatic gearbox with an ALH engine. There are a few issues that hopefully someone can shed some light on: Overheating For the last week or so the engine has been overheating to the point of engine warning lights coming on and STOP flashing on the display. The temp gauge hovers around 100 for a few mins before gradually climbing to the point of warning. The car had seperate coolant level warnings during the summer (July approx.) which was tracked down to 1) a new engine temperature sensor not fitted properly and 2) the seal on the new temp sensor had to be replaced as coolant was still leaking. Since then the engine had been running perfectly using only water as coolant. In the last week the water level has dropped and there appeared to be water on top of the gearbox below the engine temp sensor. Initially I assumed the leak had returned but I got no coolant level warnings and when the car overheated, the water was boiling in the expansion tank. I’m assuming the water on top of the gearbox may have been from the overflow. A mechanic friend of mine drained the water and replaced it with coolant, before this I could drive about 30 – 40 mins without any overheating. With the coolant I get about an hour’s driving before the needle climbs above 90. There’s plenty of hot air in the vents/fans in the dash. Having read up a little on this issue, potential causes could be the thermostat or the dreaded head gasket. Anyone got any tips on where to go from here in isolating the cause? Judder The car has developed a judder when mildly accelerating from 60kph in top gear. It’s very bad when going uphill and the only way to get it to stop is to drop a gear or ease off the accelerator. It can also occur when driving at around 100kph when taking a bend in the road. My mechanic buddy and his friend had a look and said the engine mounting on the gearbox side had a bit too much play and replaced with a mounting from a 99 Octavia. The problem remained afterwards and I’m not sure if his is due to the replacement being worn or the engine mount not being the problem. He also blocked off the EGR valve but the judder was still there. The gearbox was serviced during the summer with fluid and filter replaced, the judder was there beforehand and remained after. Another issue that may be related to this is a creaking/groaning noise when turning left at speeds above 80kph. In reading up on this I came across a forum post where someone mentioned it could be the CV joints at fault for the judder (mechanic doesn’t think so though he did say he had to repair one of the boots on one of the joints with a clip). Worst case scenario, injectors? Surge The surge occurs mostly when cold and again is very noticeable when going uphill. If I’m going 80kph and above uphill, the engine revs ‘surge’ by about 200rpm and return to normal again, this might occur a few times before the road levels out. Have put this separately but think it may be related to the judder. It’s not a serious issue but maybe of diagnostic value to someone here? Apologies for the long post but I’d like to get the car sorted as replacing it is not an option at the moment and it’s still giving me over 50mpg!