Here is one I have been scratching my head over for a few weeks (or trying to avoid the inevitable conclusion).

I have a W reg Alfa GTV 24v. It has an interesting history, owned by the editor of Car Magazine for many years. One day, in 2011, he was driving to work, and the car overheated and spat all of its coolant out (this is second hand info and is all the detail I have). Not being short of a car or two to drive, he left it in the office car park and drove other stuff. There is sat for 4 years.

In 2015, his office next door neighbour, editor of classic car weekly, bought it, and on starting it, found it had a top end rattle like nothing else. Eventually it found its way onto eBay where I got hold of it.

The rattle was easily solved. New cambelt (timing was out and belt/idlers in a bad way after 5 years standing), and let it run to pump up the tappets, and the engine is as sweet as it should be. Did a brake service and check over and it passed an MOT with no problems.

The issue is that it still spits its water out and overheats.

What I have diagnosed so far:
- No white nastiness coming out the back
- No mayo/oil mix
- I have left it idling for 5 hours and no temperature issues at all, fans cycle in and out, and sits at 90 on the gauge
- Running it up to 3000rpm unloaded for 5 to 10 minutes, temperature climbs a little but holds steady, and no problems
- Hoses harden up a little, but not rock hard (i.e. system pressurised when running but not badly
- Engine and rad have been flushed

But take it on a run, and it boils and spits out its coolant.

For example, after doing a little playing around today, I did a run through 2 villages to the petrol station, so going slowly, temp fine. Then through 2 more villages, in traffic about 50 max but generally slower, temp fine. In last village, temp moved up a little, but as one might expect, as moving in and out of parked cars, stop start etc, so fine. Then out onto fast open country roads, so opened it up, and temperature climbed to a point where I decided to stop and check under the bonnet. Temp warning light came on just as I was about to switch off.

Sure enough, it was steaming and loosing a little coolant through the reservoir cap, very obviously over-heating.

Interesting thing was that after letting it cool for about 5 minutes (totally inadequate time to cool), I started it and let it idle, and the temp dropped straight back down to 90. Drove home really slowly (just around the corner) and the temp stayed around 90.

So these are my thoughts:
- Not directly indicative of a head gasket, but I have ordered a sniffer block tester to see if there are exhaust gases in the coolant.
- Rad temp seems consistent (IR thermometer), so flow through the rad would seem OK. The fact that it can idle for hours with no issues also suggests the radiator is doing its job at lower loads
- Getting hot quickly when the engine is working hard, and temp dropping when engine is rotating slower suggests a flow issue at speed

With the above in mind, I am wondering if the impellor on the water pump is not rotating when there is a load (a typical issue on an Alfa 156 V6 which had a plastic impellor, but GTVs are meant to have metal ones).

So my next actions are:
- Sniffer test to try and rule out head gaskets
- If not head gasket, then water pump (kicking myself, I decided not to do this when I did the belts as the pump bearing felt good), and maybe radiator.
- If that then doesn't sort it, then head gaskets anyway

Now, I have never had a head gasket go before, so this is a voyage of exploration for me, confused by all the usual HG signs not being there. I would be grateful for anyone else's experience, thoughts, diagnostics etc.

I would strongly suspect the water pump is not pumping efficiently enough to cope under thermal load when car is being driven.

Possibly internal delamination of a water hose impeding flow.

An Inspection of the top and bottom hose would be my first port of call but I do agree with Pete about the pump.
Maybe change the expansion tank cap also.
Another check would be the stat.

Thanks - that makes sense.

Of interest, I happened to have a green cap off a 156 V6 which is set to a slightly higher pressure. This is what I was fiddling with today before the run. I think it made a difference in that it kept the coolant in longer to get a better read on what was happening temp wise. The old cap was definitely faulty and would let go of coolant quite quickly.

I wonder if you might find a fin or two missing from the pump impeller.

Moving towards the bottom of this sordid little problem!!!

Got a block tester sniffer test that arrived today, so ran up the engine, did the test, and...

The chemical turned yellow faster than you could say 'hmmm head gasket'!!

So I will start pulling it to bits tomorrow evening and get it sorted!! Need to find a good engineering outfit between Huntingdon and Cambridge to check the offending head(s) once I know what is going on. If there is anyone in the locality who knows or uses someone, the knowledge would be appreciated.

Can you get to Jamie Porter in Royston?

Ahh. Unlucky.
A skim of the Alfa forums suggest that V6 Busso engine head gaskets rarely fail.
Pump impellor failure causing overheating being the most likely cause but, as you say, the 2.5 had a plastic impellor which eventually fails but the 3 litre had a metal impellor which supposedly doesn't.
I suppose you'll have to take both heads off to find the blown gasket?
My 156 V6 needs a cambelt change. It's likely that I'm going to take it to Duncan at Alfanet in Bristol as he's the best value. I take my (sun) hat off to you for doing that work yourself. The timing of the crank and 4 x cams and tensioning of the belt with so little space is beyond me. I'd hate to knacker the engine by doing the job wrong.

Good luck

I'd second Alfa Workshop (Jamie Porter) and luckily just down the road from you, they are very good.

Good point on Alfaworkshop. Thats were I will be getting the new head gaskets and other bits from. I will have a chat with Jamie and get the heads over there.

I got the rear head off today, and no obvious places where the head gasket has failed, so I will get the front off tomorrow and see what is what. I'll do the water pump while it is in bits.

Belts on a 24v aren't so bad. There is actually plenty of room to get the covers off etc. Trick is to remove the OS engine mount and raise the engine or lower it to get to the various bolts for the cover and tensioners. Cam locks and a TDC gauge make getting the position easy.

I have just done the belts on our KV6 Freelander, and that is a nightmare in comparison!!

All of a dilemna with this little job now. Both cylinder heads removed, and there is nothing obvious suggesting a head gasket problem.

I must admit I have only done one head gasket in the past, and the damage was very obvious, so very interested in any head gasket experience.

I did a rough check on the straightness of the heads, using an engineers ruler and high power LED torch. Torch behind ruler, and at eye level, look for light under the ruler (from my CSE metalwork days, an engineers ruler is a heavy steel ruler with a machined and accurate straight edge, one of which I just happen to have). Its not the perfect check (difficult to see if its warped on the diagonal etc, but surface wise across the length and width both look good.

What I did find on the front head was a small pit in the alloy surface, but its not in an area where the HG is compressed (sits above one of the coolant chambers between the cylinders).

I also noticed on the rear bores, possible evidence of a dribble down the bore side of number 2, (honing not as visible, slightly discoloured) and what looks like a tide mark on number 3. The car was sat for 4 years without running after building up heat and loosing coolant, so if the HG went then, it could possibly be number 2 and number 3, with coolant leaking in slowly over a period of time.

Any experience on what to look for and what you have seen would be very appreciated.

Heads back on with new gaskets today. I started a bit late so not quite finished, but rad back in, water in, and a quick start up (exhaust manifolds only!!!!), and it starts and runs.

Got to secure the engine and finish the exahusts tomorrow, then a quick run round the block and see what the block tester shows again.

It ain't a bad little job. The Alfa V6 is a lot easier to work on than the KV6 I have been playing with in the Freelander.

I can't hold my breath any longer, Wombat!
Have you fixed it??
Fixed another suspension rattle on the 156 tonight. New lower arms? Anti roll bar bushes?
No, loose strut top nut. Phew

as Pete has said id be looking in the water pump direction

You can't buy another Busso until you've fixed this one, Wombat
Have you.......?

I must admit I am not sure

I have done head gaskets and so far it looks OK, but I needed to re-insure and tax to get out and do a proper test, which all kicks in tomorrow!!

Has a new water pump, thermostat, fully flushed, head gaskets, O rings so fingers crossed!!

Oh, and a flush and hoses checked for blockages.

So far so good.

Did 10 or so miles today and car warmed up properly, sat just below 90 on the gauge, crept up when I cam back into our village, and on switch off, no rock hard hoses, no water loss, and coolant pressure decreased without the heat soak blowing the cap.

Longer drive tomorrow morning with spare coolant, and see how it does. Then I might wash it

Ah well done.

Sounds promising.

Don't fancy doing my 156 v6 cambelt do you while you're on a roll??

I can't justify another big bill so I'm going to have to have a go myself

Im OK with busso cambelts. Got into a swing with them and have the cam blocks etc. The tricks are as follows:

- Either a proper narrow puller, or gentle tap with a hide mallet from behind to break the taper locks on the cam pullies

- TDC gauge and tipex TDC on the crank pulley and keep checking it has not moved when installing the belt

- Undo all the engine mounts except the front gearbox one,and remove the OS one from its bracket, that allows the engine to be jacked up very high and dropped down very low to get to the cover allen keys, get the water pump pulley off, and ultimately to get a torque wrench on the cam pulley bolts.
- Bit of old hose to hold the cambelt teeth in the crank pulley while the belt is going on
- Rear 2 pulleys on, and front most on (leave front inlet one off, pop belt in position, and then slip the front inlet pulley into place. Makes getting the belt on much much easier.

Shout if you need any help matey

Cheers Wombat.

I know it's not the approved way, but I'm hoping to mark all of the pulleys up and change the belt, tensioner and pulleys without cam locks and dti gauge.
I'm going to invest in tensioner tool, crank lock and slim crank pulley socket from totally alfa.

?

It is worth loosening the pullies, as you tension the belt with then just loose on the tapers which gives an even starting tension all round the belt.

Not impossible to do without, but I reckon it makes it easier, although the cam covers have to come off for the blocks to be fitted.

Its a real pain to get the belt on without the locks as the front bank does go into a safe position (cams dont get spun by the valves, but the rear bank doesn't so at some point you are trying to slide the belt on while turning two or maybe more cams with spanners to get the marks lined up. Need a few friends or be an octopus to do that.

I recently did that with a KV6 in a Freelander which only has the inlet pulleys to deal with, but was on my own and it was a real pain!!

Well, a week of commuting and a tank of fuel, and no alarming moments so far.

Temperature seems well controlled. Runs at any speed at about 80 on the gauge (seems low, but I have had a few Alfa's that read low and MultiECUscan shows the engine temp in the correct range, so a gauge error), and creeps up to about 90-95 when in traffic, but drops as soon as the fans get to work.

It is still a watching brief, but so far, so good.

That's great news. Do you think it was a dodgy head gasket that caused the over heating? Did you get the heads skimmed while they were off?

Go on, I have to ask - how much will your red 3 litre gtv be up for sale for?

Ps. Your Coop needs a wash....

There looked to be a little carbon tracing across the fire ring on cylinder 2, but it was very faint. I wonder if there was a very slight compression leak, perhaps because head nut not torqued properly. The gaskets looked OK. Fire rings evenly squashed, no debris etc, so I am still scratching my head a bit on the reason. I did a lot of reading on head gasket failure and how they fail (some of the manafacturer websites have good diagnostic info), and the only thing I could find that related was with this slight darkening sooty look on the fire ring of number 2.

I checked the heads with engineers ruler and light, and they looked spot on, so I decided to risk not getting skimmed (more impatience to get it back together than cost). It was a bit of a risk, and when I fired it up, let it run, and did another sniffer test, and it failed, I was kicking myself, but on discussion with one of the Alfa org members who runs an indie garage, chances are there is still coolant present that was contaminated. He said go off using water, engine starting to overheat etc.

It wasnt a bad job to be honest, and when you read that the engine needs to come out to get the clearance to get the front cylinder head off, its rubbish. Undid all but the NS front gearbox engine mount, and removed the OS one, and the engine lifts high enough on a jack to get clearance (fan, rad, A/C rad, and front bumper all out the way though)

Red GTV is MOTed until 21st Aug, and in current condition I would like at least 2k for it. It is not a bad car, has the belts done, and a Q2 diff, and black leather in good nick, but NS rear bushes need doing, and the paint is a bit scruffy (vandalised, not rust).

I post some pics and a description over the weekend in the right section if there is any interest

Aye, Coop very under-used at the minute, but its all in good working order. I need to do the belts and clutch in the next few months and decide what to do with it.

I've been doing mental maths over your Gtv all day, Wombat.
I've come to the conclusion that it's beyond my means currently. We're fitting a new bathroom at the moment......
I think you ought to put an ad up anyway. I'd like to see some pics of it.