The big 2.3E coolant temperature mystery

[Luuk813]

Half a year later once more, but since I got a big house renovation going on, my time tinkering with the Cabriolet is limited. Recently I finnally found a original main radiator with oil cooler for the automatic. I got it tested, and it was still in excellent condition.

After fitting it my temps are now way lower once again, between 90 - 100 when driving around at 50kph, with an ambient temp of 20C. My FLIR heat-cam also shows that the fan now dissipates heat way better, since the radiator actually gets hot evenly, and fully.

It seems that finally, after replacing bassically the entire cooling system (other then 2 still original hoses ), I can finally drive my car without any worries of overheating. Thanks to all the help of everyone on this forum.

Now to get the after-run fan working, and tune the CIS system to actually idle correctly all the time

[Tractor Dave]

The holts stuff is good.

[Luuk813]

Fixed the coolant leaks with some new original hoses, a new (aftermarket ) overflow-tank & a new original front radiator (Thank you Audi Tradition!). It was a bit of a pain in the *** to remove the coolant flange on the back of the block, since the plastic was extremely brittle. There where a bunch of pieces stuck in the block, so it broke a long time ago. No wonder it was leaking!

The temp seems to fluxuate between 100 & 105 degrees now, running on just water after letting it idle for 30 minutes. The fan kicks in consistently at the right time now that it is pressurizing correctly, so I'm quite positive on it actually being fixed this time.

Before filling the system with coolant again, I want to flush it real good. There's a bunch of rust still in the system, so I think I need a additive to use while flushing to get it out. Is there anyone that has any recommendations to remove the rust? In America people are really happy with using Thermocure, but it is unfortunatly not available in Europe

[Luuk813]

Ok, I finally had some time to do some more troubleshooting. My fuel-pump was making some weird noises from time to time, so I replaced it just to be sure. After that I found out that the coolant-temperature sensor repsonsible for informing the 2 ECU's (KE3-Jetronic) was VERY inconsistent, so I replaced that aswell.

Last sensor to replace was the O2/Lambda-sensor, since it looked liked the original one. I stripped the thread in the cat while yanking on the stuck sensor, so a local exhaust shop had to welt in a new ring .

Replacing these sensors made the car idle way more stable, so I was finally able to set my ignition timing correctly with the stroboscope. On hot-starts it still idles really low (400-600RPM), but it goed back to ~800rpm after giving it some throttle, so that's not my main concern at the moment.

The engine still runs very hot, but I found 4(!) new to me coolantleaks that will propably improve this after having them fixed. This is now my main concern. The fan kicks in late, most likely because of these leaks. Other than that I noticed that my after-run fan is not working as it should, but I'll make a new post for that issue

[K Simmonds]

Did you set up ignition timing with a fuse in fuelPump relay? The relay puts VEZ ECU in setup mode and removes ignition correction allowing to setup the ignition.

There is another way to setup ignition on NF/NG/AAR. Put the engine in TDC position and then move the crankshaft 15-18 degrees (control with flywheel marks).
Turn on the ignition and rotate the distributor slowly: when the distributor passes the mark, you hear the cold start valve engaged for a moment. That's the point you're after pretty accurately.

I knew about the fuse in the relay as that's even in the Hayns manual...But the second methond you describe is some exellent information, I didn't know about the rotating the dissy until you hear the cold start method, am guessing clockwise?

I've always just marked the base of the dissy and the head after getting the tamper proof (blooldy stupid idea) nut undo and removing it with the engine at TDC then put it back where I marked it.

[_ShurikeN]

Anyone got any tips for setting the ignition timing?

Did you set up ignition timing with a fuse in fuelPump relay? The relay puts VEZ ECU in setup mode and removes ignition correction allowing to setup the ignition.

There is another way to setup ignition on NF/NG/AAR. Put the engine in TDC position and then move the crankshaft 15-18 degrees (control with flywheel marks).
Turn on the ignition and rotate the distributor slowly: when the distributor passes the mark, you hear the cold start valve engaged for a moment. That's the point you're after pretty accurately.

[Luuk813]

Well, happy new year everyone! My year ended on a high-note, since I finally fully assembled the engine on the 30th of last month. The car now runs and drives, albeit not yet perfectly.

Tips for any other noobies replacing their headgasket for their first time on this engine:

- Make sure to remove the starter before even trying to remove the downpipe, otherwise your access will be terrible and you'll waste a day trying to remove the (4... I thought there where only 3 since I couldn't see the last one...) bolts just like I did.
- The top starter bolt is removed from the rear of the transmission bell housing, not from the front like the bottom bolt is....
- If the injectors seem stuck, just pull on them extremely hard. You don't need to unbolt the injectors from the fuel distributor at this point. Trying so will only bent the hard-lines. Just pull back really hard and the o-rings holding them in will eventually come loose.
- Connecting the vacuum system on top of the engine can be a pain. Try connecting all hoses to the rubber intake piece first before installing it and connect the other ends of the hoses later to make sure you'll still have partial access.

The big question is, did it fix my overheating issue? Well, there sure is a lot less pressure on the reservoir cap when the engine is fully warmed up now. The temp gauge still shows around 100 - 105 degrees when idling for a while, but I guess that's still within spec. It is however showing that temp with fan running all the time. The fan came on suddenly and never stops, even when stopping the engine. Perhaps it's just the relay that is stuck?

I'm currently working on sourcing both radiators to replace my current ones, since they're both not in the best of conditions. I'll post my new temperature readings here once I got them installed.

One thing I couldn't really get right after assembling the engine was the ignition/distributor timing. Setting it to TDC wasn't that hard, but using a timing light to set the timing to 15 degrees before TDC, like the specifications call for, was more difficult since I couldn't see the markings on the flywheel clearly. Later on I used a small paint marker to mark the 15, but it was still jumping around way to much for me to say clearly see it. In the end I just set it where it sounded the most healthy and left it there for now. Anyone got any tips for setting the ignition timing?

[K Simmonds]

That bolt can often be an 8mm Allen head on one end and a 17mm nut on the other end, looks like you've got an 8mm Allen head on the starter moter side.

[Luuk813]

Great, then I can finally continue after removing that one! If only I wasn't so stubborn on trying to remove it from the front, then I would have saved myself quite some time and a lot of swearing

Thanks again!

[Tractor Dave]

One bolt is threaded and the other passes through with a nut and washer on the other side.

[Nuvo]

The bolt head is the top arrow, you need to undo that from the transmission side.
The bottom nut/bolt is accessed from the bottom (you need to counterhold either the nut/bolt), the top one is accessed from above.

[Luuk813]

Just been reading through this thread again over a cup of coffee, using an impact gun on the crank bolt isn't the end of the world, it is however the end of your crank cam belt pulley. Don't be tempted to save a few Euro's and reuse it, throw it in the bin. It does say in the factory manual not to use an impact gun but you we're to know so don't beat yourself up over it, just buy a new one. Terrybullwon on here makes billet bottom pulleys that last forever, they're a few quid but not too expensive for what you get IMO, if your planning on keeping the car a long time I'd personaly try and use one of them.

Daves right to notice all the gunk in the water chanels in the block, looks like it's spent a long time stood with either water or poor quailty coolant at some point, the water holes in the head gasket are quite small and it's fairly normal to get some build up of contamination on the underside, though that is quite a lot. That said in the later pic where you've cleaned off the deck they don't look so bad at all, the corrosion around them isn't great but not terrible either. Giving the deck another going over as I described in my last post might reduce some of it and a new head gasket will seal up fine.

Anyway considering you've not taken an engine appart before your doing great.

On first start up just use tap water and two or three tins of coolant system flush as it's a large capacity system, use a cheap oil to flush as well as I suggested above, let it run up to opperational temp then drop those fluids out and refill will decent quality coolant and oil and the engine should be fine for another 30 odd years with regular maintainance.

Thank you for the great advice! I lightly sanded the block like you suggested, and the results are definitely much better. It's now almost time for me to put the head back on again. Before I do that however, I need to tackle my problem regarding removing the starter motor. The bottom bolt holding it in came out just fine, but the top one is completely rounded. So much so that I can't even identify it as ever having been a bolt:

PXL_20230930_131245605.MP.jpg

Is there perhaps something I'm missing here, or did the previous owner just really mess up the bolt by this much? I noticed that the bolt holding in the transmission (top red arrow) is is on the exact same height as the "bolt" on the starter. Is it perhaps so that what I refer to as the starter bolt is just the end of the transmission bolt?

For you guys that removed the starter motor before on these type of engines; did you just simply remove the top and bottom bolts from the front of the starter, or may my theory about the transmission bolt be correct? If you should actually be able to remove it from the front, then I'm open for suggestions on removing the rounded bolt, since access is really tight, and nothing that I tried so far worked at the slightest

[K Simmonds]

Just been reading through this thread again over a cup of coffee, using an impact gun on the crank bolt isn't the end of the world, it is however the end of your crank cam belt pulley. Don't be tempted to save a few Euro's and reuse it, throw it in the bin. It does say in the factory manual not to use an impact gun but you we're to know so don't beat yourself up over it, just buy a new one. Terrybullwon on here makes billet bottom pulleys that last forever, they're a few quid but not too expensive for what you get IMO, if your planning on keeping the car a long time I'd personaly try and use one of them.

Daves right to notice all the gunk in the water chanels in the block, looks like it's spent a long time stood with either water or poor quailty coolant at some point, the water holes in the head gasket are quite small and it's fairly normal to get some build up of contamination on the underside, though that is quite a lot. That said in the later pic where you've cleaned off the deck they don't look so bad at all, the corrosion around them isn't great but not terrible either. Giving the deck another going over as I described in my last post might reduce some of it and a new head gasket will seal up fine.

Anyway considering you've not taken an engine appart before your doing great.

On first start up just use tap water and two or three tins of coolant system flush as it's a large capacity system, use a cheap oil to flush as well as I suggested above, let it run up to opperational temp then drop those fluids out and refill will decent quality coolant and oil and the engine should be fine for another 30 odd years with regular maintainance.

[K Simmonds]

Just had a good look at your photos, you've done a pretty good job of cleaning the deck though I would go over it again as I described.

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[K Simmonds]

Clean the top of the block with course sand paper on a flat block until you get a semi shiny surface. Try and use good quality stuff that doesn't shed too much sand and dust, I find 80 grit 6" sanding discs perfect for the job. The oil ways will clean themselves on the first start. I always use cheap 10W-40 for the first start let it run up to operation temperature, then drop that out to get rid of any debris in the sump. Then use a better quality 10W-40 for an 7A/NG motor along with a fresh filter.

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