900 B230FK head - waterways sealed - why??

[eeedelli]

Hi folks,

After the most *ridiculous* delay (6½ weeks!!) at the machine shop, I've finally got the head back from crack testing, skimming (which they first said it didn't need anyway - which made sense to me as I caught it before it overheated) and re-assembly.

They didn't acid dip it either so the same crud that appeared to be blocking some of the waterways was still there.

I was just grateful to be able to get it back and get on with it so I said I'd clean those out manually. To speed the job up I grabbed my drill and started to poke through. 'Lo and behold', I've hit fresh alloy beneath! (You can see that in the bottom LH port in the picture of the head.) I've been searching the 700/900 FAQs but nobody seems to comment on it and I can't see a picture of a head anywhere to compare.

Are some of the waterway holes that are clear in the block not aligned with holes in the head? If so, I would assume that this is a deliberate policy to force water flow round the whole system rather than some of it possibly 'short cycling' round between the head and block but not really being transported away to provide proper cooling. Alternatively, is there a chance that this has had a head changed off (e.g.) a 740 or 240 non-turbo, if that has different waterways?

However, where the ports are sealed, it suggests that cooling will never really be able to occur properly there, so I'm wondering whether they were supposed to be drilled out anyway and why would they leave the holes in the head gasket allowing the alloy head to corrode?

The consequence of water coming up from the block and sitting against the alloy is that they are really badly corroded (2-3mm deep) so I suspect some twit has been running it without antifreeze for quite some time. It seems to be the front ports on cyls 1-3 on the exhaust side (which is where you'd think you really wanted maximum circulation, with the heat from the turbo etc), the rear port on cyl 1 on the intake side and the 2 small ports right at the back behind cyl 4 (which, again, must suffer from poor airflow so you'd think maximum water circulation would be desirable).

Has anyone else found this issue when changing a head and, if so, what (if anything) did you do about it?

Incidentally - what do we think about red/orange (OAT) vs green/blue (traditional) antifreeze? (I changed to OAT when I got this one about 5 years ago but I'm wondering whether that's contributed to the problem. The gasket went on cyl 2 which steam cleaned itself nicely in the 15 mins I was driving before I pulled off the fast road and noticed it was running on 3 cyls when I stopped.) It's difficult to draw any particular conclusion about which antifreeze type is best from the info that's in the FAQs.

I was looking at Evans waterless recently but it's hideously expensive. My cousin has just put me on to this, which he used in a Rover P4 about 40 years ago. https://4lifecoolant.co.uk/features Don't know whether any of you have used it? A little more searching has just found this, which is even better value if you have several cars to do. https://www.azureliquidsolutions.co....gine-life-25l/

Thanks,
David.

[Laird Scooby]

DON'T use the red OAT stuff in your engine - it will corrode your block and if it happens to mix with any original ethylene glycol, the engine is scrap - oh yeah and it eats gaskets on pre 2000 cars!

Give the entire system a run for a month on plain water then add a flushing agent. Drive for half hour and park it up overnight.
Next morning, remove the thermostat and refit the 'stat housing, run it for 10-15 minutes to circulate the water and flushing agent.

Remove the bottom hose at the radiator, let it drain and then refit. Remove the top hose at the radiator and take you garden hose and insert it into the top hose (should be directed to the 'stat housing at this point) and turn the hose on.

Presently cloudy water should start coming out of the radiator top hose stub. Let it run for at least half hour and make sure it's clear. If not, let it run until it's been clear for at least 10 minutes.

Turn the hose off and again, drain the system by removing the bottom hose from the rad and refitting.

Fit a NEW thermostat and seal and refit the 'stat housing and top hose. Next, add 5L of concentrated ethylene glycol anitfreeze through the expansion tank, squeezing the bottom hose as necessary to help "burp" the system. Top up to the correct level with plain water.

Refit the exapnsion tank cap, start the engine and run it up to temperature. Switch off and leave it overnight to cool down. Top up to the correct minimum/cold level with plain water. You already have the right amount of antifreeze in there so any shortfall has to be water.

Keep an eye on the cold level over the next few days and if your heater is manual, make sure you select the hottest setting before doing any of the draining/flushing/filling.

As for that waterless coolant, i wouldn't bother - it's been shown to cause leaks, partcularly from other members on here reporting it on red blocks and in one case, potentially a head gasket failure.

Volvo keep concentrated ethylene glycol at reasonable prices as do most motor factors. The OAT stuff was developed in the late 90s by the Japanese for all aluminium engines because they didn't like the damage EG antifreeze caused to them. However, as pointed out earlier, OAT attacks cast iron and gaskets made before 2000 and isn't suitable for redblocks.

[eeedelli]

Thanks Dave.

I'm surprised to hear that the waterless coolant can cause leaks, considering that part of the point of it is that it doesn't build any pressure and is often aimed at classic cars. Therefore, I'm puzzled as to why it would do that.

Oh yes - any ideas on the thinking behind the sealed waterways issue, too?

D.

[Forrest]

There’s an old thread on Turbobricks about those blocked off coolant passages. Basically, they don’t exist on that cylinder head and the coolant has etched them into the metal. This process was probably exacerbated by the OAT coolant.

http://forums.turbobricks.com/showthread.php?t=157047

[Laird Scooby]

Originally Posted by eeedelli

Thanks Dave.

I'm surprised to hear that the waterless coolant can cause leaks, considering that part of the point of it is that it doesn't build any pressure and is often aimed at classic cars. Therefore, I'm puzzled as to why it would do that.

Oh yes - any ideas on the thinking behind the sealed waterways issue, too?

D.

My suggestion on the waterways is more or less what Forrest said above. As for the Evans coolant not building pressure, unless you relieve the pressure it will still build because it's a sealed system. Simple laws of Physics.

Another point on the waterways is that if you consider the water pump pumps the coolant into the front of the head, round the block and out of the head with a return from the block to the pump as well (it's tricky to explain but you get the basic idea), it makes sense that some parts are blanked off because the casting process usually doesn't allow for exact ways to be cast in the block so the head blocks those that aren't needed.

As they blockages appear to be from the factory, i'd call it good and hope for the best after the rebuild.

[eeedelli]

Yeah - I'm not going to faff about drilling them out, I think. There must have been some heads with those ports open at some time, otherwise the gaskets wouldn't have the holes, so my suspicion is that they'll have experimented and reduced some unproductive turbulence by blocking some of them.

Interesting to see the head on the turbobricks forum that's had them drilled out but I suppose you need every bit of flow you can get when you're racing (which I'm certainly not!)

Re: the waterless stuff. I think the whole point is that it doesn't expand anything like as much as water does and that's what keeps the pressure down. I remember seeing it demonstrated somewhere. They had an engine that was being brought up to full temperature and then they removed the cap. There was no pressure released and no change of level as they did so. That's got to put less stress on the whole system than having it running at 1½ bar when hot.

Incidentally, reading the info on the 4Life pages, theirs *isn't* completely waterless and is designed for use in inorganic systems that were intended for ethylene glycol and can even be mixed with that in an emergency. Presumably, theirs is still a pressurised system because of the small amount of water present, though it's probably still reduced pressure if the expansion of the majority of it is less than water, though the water in it presumably provides lower viscosity and better heat transfer than purely waterless stuff.

Tricky to know what to do, really.

[Laird Scooby]

Originally Posted by eeedelli

Tricky to know what to do, really.

The best course of action David is to use what Volvo recommend - ehtylene glycol and give it a good reverse flush (as i described earlier) and keep the pressure in there.

Don't forget the stuff your friend (cousin?) used in a Rover P4 is designed for cars with very inefficient water pumps and fans, if they have any at all - many older cars relied purely on thermosyphon to move the coolant around!

Those that know me may find this last comment a little hypocritical given i often suggest adding 0.5-1.0L of Carlube ATF-U to the engine oil and using it in auto gearboxes instead of the better known Dexron II-D or equivalent. However it has been well and truly tested and proven countless times.
However i wouldn't suggest running purely on it as engine oil (although i've seen it done with some interesting positive results on a lawnmower engine on YT) but using it as an additive to the engine oil works well.
Still needs a good quality 10W40 for the rest of the engine oil though!

However, don't forget these engines have their roots way back in the 60s in the 120/140 series Volvos (and the P1800) when OAT wasn't even a glimmer in Mr Japanese-Scientists eyes. Ethylene Glycol was the "go to" antifreeze when it was used.

Also newer fluids, despite what the marketing men tell us, aren't always backwards compatible - in the USA Honda faced a class-action lawsuit for telling customers their new DW-1 ATF was backwards compatible with those vehicles needing Z-1 ATF (discontinued in favour of DW-1) and thousands of fried torque converters later the customers took Honda to court and won.

As i said at the start of this post, stick to Ethylene Glycol and you won't go far wrong. Many have tried changing to different types of antifreeze and most if not all have returned to EG for various reasons.

[eeedelli]

Oh - I've not come across the ATF in engine oil before. What's the aim of doing that?

It's interesting to note that the ForLife version of antifreeze has been around for decades - as you say - but it was developed for racing engines that normally took EG but needed more effective cooling while being compatible with that. My guess is that the reason it's still water-based is to provide the required low viscosity and, hence, cooling efficiency.

I'd have thought that if there were significant shortcomings of the sort you describe in the Honda debacle, they would have come to light long ago.

I'm surprised there aren't any research papers that have investigated these parameters. (Well, I''m sure there are - I haven't looked around!) It's always good to have independent empirical test data.

[230ina245]

Some corrosion like that is quite common on most heads, but not nearly as bad as that unfortunately. I would be slightly worried about the amount of gasket clamping area that is left between the corroded area and first bolt hole (bottom left on first picture). You mentioned overheating in your first post - was this because the head gasket had blown and where did it let go? I'm worried that those corrosion areas will still be a weak spot
You can get the corrosion holes filled (welded) but it may be expensive and would need skimming again. Do you know how much it was skimmed already?
Anyone else got an opinion?
Tim

[Laird Scooby]

Originally Posted by eeedelli

Oh - I've not come across the ATF in engine oil before. What's the aim of doing that?

It's interesting to note that the ForLife version of antifreeze has been around for decades - as you say - but it was developed for racing engines that normally took EG but needed more effective cooling while being compatible with that. My guess is that the reason it's still water-based is to provide the required low viscosity and, hence, cooling efficiency.

I'd have thought that if there were significant shortcomings of the sort you describe in the Honda debacle, they would have come to light long ago.

I'm surprised there aren't any research papers that have investigated these parameters. (Well, I''m sure there are - I haven't looked around!) It's always good to have independent empirical test data.

Using ATF in with the engine oil has many benefits, it cleans the engine gently including the gum/carbon deposits on valve guides and piston rings reducing sticking and oil burning and improves compression as a result. This has a nice knock-on effect of improving emissions too.
It also revives tired oil seals because of the additive used in ATF to condition the seals in an auto-box. This helps prevent and in some cases cure oil leaks.

On cars with hydraulic tappets, it helps to free them off restoring quiet operation and correct valve lift.

There are some other possible benefits but i'm not sure whether they are a direct result or an indirect result, either way they're improvements.

With the Honda thing, many owners in the USA successfully sued Honda, the stuff that was on the net about it seems to have all but disappeared now, i suspect Honda threw a lot of money at it to get it removed.

Something to bear in mind about fluids developed for racing - the fluids are changed after each race. It's unlikely there will be any long term test results from anything that has been used in race situations.