heathrobinson
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1.9 PD Tdi overheating problemheathrobinson
@heathrobinson
Club Retro Rides Member 111
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Hi all
I've got an Audi A4 with a 1.9PD lump in it, the AVF if I remember correctly. Yesterday it decided to overheat pretty heavily on the way back from town. I was driving at a bit of a lick down the back lanes, but not revving it that hard, and it cooled off pretty sharpish after I did a bit of coasting down hill and using the torque in higher gears back up hill. When I got home, the fan stayed on for longer than normal after the car stopped, but when I checked the fluids everything is bang-on. It's never used any water, yesterday included, and it only goes through oil very slowly, as I think the turbo's seen better days. The water pump is pretty new, as it was done with the cam belt about 20k ago, and the coolant looks clean and fresh. There's no mayo in the oil, and it doesn't seem to be breathing much at all.
Anyone got any ideas/things to look at? Ta!
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zeberdee
Club Retro Rides Member
Posts: 938
Club RR Member Number: 2
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Could try & look at the thermostat , seee if it’s opening fully .
Was it a genuine water pump ? I’ve heard there common for the impeller to spin on the shaft when hot .
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gte86
Part of things
Posts: 611
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Does the temp gauge sit in the middle? I've seen loads with the stat stuck open and the gauge only sits at 1/3. I've had one before with a stat stuck shut and that just overheated but the gauge was very slow to react. For what it costs I'd try the stat first. Remember they twist out once they are unbolted iirc
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heathrobinson
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Broken everything
Posts: 848
Club RR Member Number: 111
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1.9 PD Tdi overheating problemheathrobinson
@heathrobinson
Club Retro Rides Member 111
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Thanks guys
I ordered a stat as soon as I got back, though it seems to me that it's not likely to be that - It went from a steady 90c (the half way mark) most of the way back up to at least the 3/4 mark after the long hill into the village. It went back down fairly quickly when I started taking it easier, and sat at 90c for the rest of the journey. I'll see if I can find any info on the pump, but it was a dealer-stamped belt change, before my ownership. I'm assuming that they used a genuine Audi item
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gte86
Part of things
Posts: 611
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When the stat is out you may be able to feel the back of the pump. I've seen them come loose before and the pump just spins on the shaft
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mk2cossie
Club Retro Rides Member
Posts: 2,954
Club RR Member Number: 77
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Is it actually overheating, or just saying it is? As a lot of the VAG stuff has temperamental coolant temp sensors, and from experience I'd only trust a genuine replacement
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We had a 1.9PD in a Seat Altea, that suffered the slow failing headgasket, and used to airlock in the heater matrix, which was how we found it as it only used a tiny amount of water. Couldn’t see any Mayo, just a trace of black in the expansion tank
Don’t know enough, but just a thought, could it be the slow failing headgasket pushing an airlock around? Think that would give a low reading if air was sat wheee the sensor was though
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Jul 11, 2021 10:23:43 GMT
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AVF is the 130 Audi engine, its the same as the ASZ VW one. The ASZ are prone to the head bolts stretching and causing head lift under boost, which in turn causes overheating while under load/boost. When it does the overheat, the interior heater should loose some of its heat output. Easy way to check for this is when its left overnight, the next morning loosen off the expansion bottle cap, if theres pressure in it the head gasket and bolts are failing. Hope this helps.
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xfu990
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Posts: 78
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Jul 11, 2021 11:15:14 GMT
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Is it actually overheating, or just saying it is? As a lot of the VAG stuff has temperamental coolant temp sensors, and from experience I'd only trust a genuine replacement This!
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1.9 PD Tdi overheating problemballbagbagins
@ballbagbagins
Club Retro Rides Member 164
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Jul 11, 2021 13:47:12 GMT
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Is it actually overheating, or just saying it is? As a lot of the VAG stuff has temperamental coolant temp sensors, and from experience I'd only trust a genuine replacement This! I've had this, twice.
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Jul 11, 2021 15:18:14 GMT
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Sounds like a flow problem. Water pumps can fail no matter what brand. HG is unusual if the car has been maintained.
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Needs a bigger hammer mate.......
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heathrobinson
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Posts: 848
Club RR Member Number: 111
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1.9 PD Tdi overheating problemheathrobinson
@heathrobinson
Club Retro Rides Member 111
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Jul 14, 2021 16:29:18 GMT
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Does anyone have the address for the VW engineer that thought putting the thermostat housing pretty much underneath the alternator bracket was a good idea? I want to pop round and have a quick word...
I need to go for a more extensive drive, but I think that a new stat has done the trick. For future reference, yes, you can swap the stat without taking the alternator, or it's bracket, off. Is it fun? No. Not even a little bit, unless you have tiny hands and arm bones made of jelly, which I don't. There's a wealth of adversely-situated plumbing contrivances, wires, and pointy metal items all jostling for the privilege of being the next to draw blood.
I actually have a set of uprated head bolts (part of a delayed turbo-upgrade plan) somewhere, so if things prove to be fixed, then I might pop them in sooner rather than later. If things aren't better, then I also have and a decent multi-layer head gasket too, so that's not the end of the world. I've only done 3 journeys since I saw the first sign of overheating, and it never got over the 3/4 mark, so I'm fairly confident that no damage has been done.
I can't see it being the sensor - the way it happens, and the accompanying symptoms, don't make sense for that. It wasn't really easy to get a finger to the impeller of the pump, but from what I could feel, it was all OK.
Thanks for the advice one and all
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Jul 14, 2021 16:54:59 GMT
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How dare you have the audacity to fix your own car!!!😱 Seriously, glad you seem to be sorted 👍
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xfu990
Part of things
Posts: 78
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Jul 14, 2021 17:25:51 GMT
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Nice one, glad it's sorted. We've had two recent thermostat issues, both can be put down to eurocarparts tat unfortunately. Both stats only replaced whist other work ongoing (preventative maintenance!) One was complicated further by one of their (euro) sensors (VW 1.9TDI) original parts fitted, no issues. You live and learn, some of us have to do it twice though
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heathrobinson
Part of things
Broken everything
Posts: 848
Club RR Member Number: 111
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1.9 PD Tdi overheating problemheathrobinson
@heathrobinson
Club Retro Rides Member 111
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Jul 20, 2021 11:55:56 GMT
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Well this is just getting confusing... Changed the stat, drove it for a few days, including a "spirited" blat from one side of Devon to the other and back, no problems at all. Then today, during a gentle drive to get a PCR test (grrr), back to square one! I can only assume that I fingered the impeller back onto it's shaft enough to make it behave its self for a few days. So that's rubbish.
Water hasn't dropped a mm, oil still clean and nice, no adverse pressures under either cap etc, so it pretty much has to be the pump doesn't it.
Now, to change the pump, I need to take the cam belt off. The belt's done a bit less than 40k, but it feels a bit daft not to change that while I'm at it, and the cams are probably a bit worn, as I've never got the mileage I should out of it, so I guess that they should be done at the same time. being as I'm looking at all this work, is there anything else that I should be doing at the same time?
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mk2cossie
Club Retro Rides Member
Posts: 2,954
Club RR Member Number: 77
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Jul 20, 2021 13:08:18 GMT
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Genuine VW replacement coolant temperature sensor would be my only other suggestion before all that work But with 40k on a belt, I'd replace the lot with a Gates kit, unless you know the exact history of what was changed on the last belt
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heathrobinson
Part of things
Broken everything
Posts: 848
Club RR Member Number: 111
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1.9 PD Tdi overheating problemheathrobinson
@heathrobinson
Club Retro Rides Member 111
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Jul 20, 2021 18:50:37 GMT
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Genuine VW replacement coolant temperature sensor would be my only other suggestion before all that work But with 40k on a belt, I'd replace the lot with a Gates kit, unless you know the exact history of what was changed on the last belt Yeah, that was my thinking - there's no point in not doing it, and I'll not have to think about it again for years. I reckon a genuine water pump, genuine stat and temp sensor, Gates belt kit, and probably new idlers for the serp belt, as something there sounds a little noisy.
I've been looking at the ZedPerformance cam kit (just a normal cam, there's no advantage to anything fruitier until you're at about 300bhp apparently), as they seem to be a good compromise between quality and cost.
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Intermittent faults, don’t you just love them 🙄 Good luck
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Jul 21, 2021 12:13:20 GMT
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If you have a car that starts well / runs well, why would you be worrying about cams? They actually last well if the car has been properly maintained with the right oil.
Nick
PS. Meant to also say, I’m right with you on wanting the address(es) of certain VAG design engineers. I’ve got a bit of list of things I’d like “a word” about! The top pinch bolt on that daft multi-link front suspension is top of the list just now…..
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Last Edit: Jul 21, 2021 13:12:06 GMT by vitesseefi
1967 Triumph Vitesse convertible (old friend) 1996 Audi A6 2.5 TDI Avant (still durability testing) 1972 GT6 Mk3 (Restored after loong rest & getting the hang of being a car again)
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heathrobinson
Part of things
Broken everything
Posts: 848
Club RR Member Number: 111
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1.9 PD Tdi overheating problemheathrobinson
@heathrobinson
Club Retro Rides Member 111
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If you have a car that starts well / runs well, why would you be worrying about cams? They actually last well if the car has been properly maintained with the right oil. Nick PS. Meant to also say, I’m right with you on wanting the address(es) of certain VAG design engineers. I’ve got a bit of list of things I’d like “a word” about! The top pinch bolt on that daft multi-link front suspension is top of the list just now….. The reason I think they're an issue is that I took it in to a good Audi tuner a while back, to talk about it being down on MPG and whether there could be a problem with the remap I have on it. He had a look over it, and said that he was pretty sure that it was the early stages of a very common problem with these engines - the factory cam shafts are made of the stuff Dairy Lea couldn't use for their cheese wrappers. I'll have the cam cover off before I spank £300 on a replacement, but he sounded like he was pretty certain that I'd find less lobe than I'd really wish for
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