Engine Coolant Hose Help Needed

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guzzit3
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Engine Coolant Hose Help Needed

Post by guzzit3 »

I've recently aquired an early non-SE Excel and it's a bit of an unfinished project by the previous owner. The car came with some blue aftermarket silicone hoses, but it looks like they reused some of the orignal hose and made some sort of heater matrix bypass and used some copper 'T' pieces that look like they are for house plumbing! Here's a pic, I've removed the airbox for better access, and the blue hoses connect the engine to the heater in the dash:

Image

I'm not sure what the purpose of these 'T' pieces are or why the bypass pipe is there, and I was wondering if it was safe to remove this bypass pipe? I'm not really sure what it's supposed to do. I did look in the workshop manual, but the pages in mine are pretty hard to read for the cooling section, and it only shows the routing of the large diameter radiator hoses from the engine to the radiator.

Also I plan to replace the hoses with the original hoses if possible, so I can use the proper routing and mounting clips. Is there a good place to order these? SJ Sportscars seem to stock them, but I couldn't find anywhere else selling them. I don't need a full set of hoses, just the smaller diameter ones.

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Re: Engine Coolant Hose Help Needed

Post by Pete Boole »

I'm not familiar with the early heater arrangement but the later cars have a bowden cable operated heater valve. It is a bypass type - when the heater in the car is set to heat the coolant passes through the heater matrix and then back into the cooling system; when the heater is off the coolant bypasses this valve (and heater matrix) and returns to the coolant system. This allows coolant from the bulkhead end of the cylinder head to circulate - without the bypass type heater valve (ie - if it was just an on/off valve) there is no circulation in the rear of the head and localised overheating can occur. Even if the early cars didn't have this sort of valve I would try to install one.

Pete

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Lotus-e-Clan
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Re: Engine Coolant Hose Help Needed

Post by Lotus-e-Clan »

This is a non-std mod that a few of us have done because full coolant distribution around all 4 cylinders is only acheived with the heater valve open. Mike @ Lotusbits does this mod for his rally engines - he had seen too many No 4 cooling issues, hence the extra heater bypass hose mod.

My 89SE has a simple non-bypass heater valve as an original fitment.

When the heater valve is open, coolant is drawn from the hose stub at the (N04) far-end of the head and returns to the thermostat housing (pre-stat). When the heater valve is closed, circulation around No4 cylinder is compromised because the coolant return from N04 is via the inlet manifold coolant rail only, and this falls short of the full extent of the head, thus hot spots can develop around No 4 cylinder with the valve closed.

Also I can vouch for 15 mm Domestic heating copper tee pieces. I've used them for at least 15 years with no issues in both Clan and Excel....just need to solder a straight yorkshire connector on the tail ends to provide a hose bulge to prevent leaks when using a single clip ..otherwise double clip them if the tails are just plain 15mm copper pipe. Of course a nice 16 mm nylon tee is a better solution ..but you never have one to hand when developing coolant mods!!

My cooling system is highly modified mind you. I fitted an EWP to replace the std water pump and use Evans waterless coolant. But you can see how the heater bypass mod works in my system below. It might not help you too much, but trying to make sense of it is good for a laugh!
Image

Image
Image
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Re: Engine Coolant Hose Help Needed

Post by bash »

Ive used quite a bit of copper pipe and fittings on my v8 and havnt given any problems over a few years.
viewtopic.php?f=7&t=8397&start=45

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guzzit3
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Re: Engine Coolant Hose Help Needed

Post by guzzit3 »

Thanks very much for the info and posting up the pics, it makes much more sense now why the bypass is there. I guess the previous owner had done this mod, the only downside I can see is that when the heater valve is fully open, some of the hot water would still pass thru the bypass pipe, but I guess this is better than a hot cylinder 4!

I think a 3 way valve would be a really nice solution here, but it needs to be pressure and temperature rated, so it's not the sort of thing that I'd find in B&Q - I'll have to do some searching.

As for the copper fittings, while they probably do the job, it's possible you may have issues in the future. When is copper when combined with aluminum and water it will corrode over time, which is why I'm after some non-copper fittings if they are available.

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Re: Engine Coolant Hose Help Needed

Post by Pete Boole »

Take a look at T7 Design's website - lots of heater valves. They are very happy to help with queries as well.

Pete

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Re: Engine Coolant Hose Help Needed

Post by Lotus-e-Clan »

guzzit3 wrote:
Thu Jun 10, 2021 15:21
Thanks very much for the info and posting up the pics, it makes much more sense now why the bypass is there. I guess the previous owner had done this mod, the only downside I can see is that when the heater valve is fully open, some of the hot water would still pass thru the bypass pipe, but I guess this is better than a hot cylinder 4!

I think a 3 way valve would be a really nice solution here, but it needs to be pressure and temperature rated, so it's not the sort of thing that I'd find in B&Q - I'll have to do some searching.

As for the copper fittings, while they probably do the job, it's possible you may have issues in the future. When is copper when combined with aluminum and water it will corrode over time, which is why I'm after some non-copper fittings if they are available.
You can get 16 mm nylon t-joints no problem.
Whilst the theory on copper/alum/water dissimilar metal corrosion is sound, in practice a 50:50 mix of antifreeze and purified water (distilled or deionised) mitigates the risk. BTW, your radiator and water pump will leak long before you see any corosion in your copper joints ... ask any long term Excel owner :) . For me, I use waterless coolant anyhow, but not specifically to stop corrosion in my joints, but that's another real-world story (contrary to some of the incomplete thinking you'll find on the net). :roll: .

Also the heater bypass hose circulation in my modified system is 'dead' when the heater valve is open. The heater return is directly at the pump input, the bypass return is at the stat ...two very different sucking behaviors if you get my drift. Heater runs as hot as a normal system.
Last edited by Lotus-e-Clan on Sat Jun 12, 2021 07:51, edited 1 time in total.
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Re: Engine Coolant Hose Help Needed

Post by bash »

I also use a 50 50 mix that will prevent corrosion. I also store any water from my dehumidifier for fill ups, free pure distilled water, which is better for cooling. (We use it in the steam iron too...... Without the antifreeze tho )

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Re: Engine Coolant Hose Help Needed

Post by Tanz »

bash wrote:
Fri Jun 11, 2021 08:24
I also use a 50 50 mix that will prevent corrosion. I also store any water from my dehumidifier for fill ups, free pure distilled water, which is better for cooling. (We use it in the steam iron too...... Without the antifreeze tho )

Bash
I too use a 50/50 mix but with deionised water. Where I live the water is very hard. Forever cleaning the kettle and shower head. The excels water is always clean and the radiator was recored 11 years ago and still seems fine.
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guzzit3
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Re: Engine Coolant Hose Help Needed

Post by guzzit3 »

Pete Boole wrote:
Thu Jun 10, 2021 19:03
Take a look at T7 Design's website - lots of heater valves. They are very happy to help with queries as well.

Pete
Thanks, that's a great site, this valve looks like it should do what I'm after:

https://www.t7design.co.uk/tx2-heater-b ... b-560.html

I'll have to double check if I need push or pull to bypass, and I think I'll pick up a new bowden cable and few fittings also.
Lotus-e-Clan wrote:
Thu Jun 10, 2021 21:38
Whilst the theory on copper/alum/water dissimilar metal corrosion is sound, in practice a 50:50 mix of antifreeze and purified water (distilled or deionised) mitigates the risk. BTW, your radiator and water pump will leak long before you see any corosion in your copper joints ... ask any long term Excel owner :) . For me, I use waterless coolant anyhow, but not specifically to stop corrosion in my joints, but that's another real-world story (contrary to some of the incomplete thinking you'll find on the net). :roll: .
Thanks, I'll pick up some nylon fittings, and make sure they are the type intended for car temps + pressures. I'm planning on just using pre-mixed blue type coolant, nothing fancy but I've checked and it does have corrosion inhibitor.

Yep, with Alu / Copper / Water in a system, the Alu will always corrode and the copper will be fine:

Image

Source: https://aluminumsurface.blogspot.com/20 ... m-and.html

So the copper fittings would outlast the water pump / radiator / heater matrix / etc.

If people want to use copper and it works for them then that's cool with me, I don't judge! :D I just try and avoid it myself unless there is a special reason to use it.



Thanks again everyone for all the help with this, I'll have to do a bit of waiting for the parts to arrive but I've got plenty of other things to sort out in the meantime.

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Re: Engine Coolant Hose Help Needed

Post by Lotus-e-Clan »

guzzit3 wrote:
Sat Jun 12, 2021 16:29
Pete Boole wrote:
Thu Jun 10, 2021 19:03
Take a look at T7 Design's website - lots of heater valves. They are very happy to help with queries as well.

Pete
Thanks, that's a great site, this valve looks like it should do what I'm after:

https://www.t7design.co.uk/tx2-heater-b ... b-560.html

I'll have to double check if I need push or pull to bypass, and I think I'll pick up a new bowden cable and few fittings also.
Lotus-e-Clan wrote:
Thu Jun 10, 2021 21:38
Whilst the theory on copper/alum/water dissimilar metal corrosion is sound, in practice a 50:50 mix of antifreeze and purified water (distilled or deionised) mitigates the risk. BTW, your radiator and water pump will leak long before you see any corosion in your copper joints ... ask any long term Excel owner :) . For me, I use waterless coolant anyhow, but not specifically to stop corrosion in my joints, but that's another real-world story (contrary to some of the incomplete thinking you'll find on the net). :roll: .
Thanks, I'll pick up some nylon fittings, and make sure they are the type intended for car temps + pressures. I'm planning on just using pre-mixed blue type coolant, nothing fancy but I've checked and it does have corrosion inhibitor.

Yep, with Alu / Copper / Water in a system, the Alu will always corrode and the copper will be fine:

Image

Source: https://aluminumsurface.blogspot.com/20 ... m-and.html

So the copper fittings would outlast the water pump / radiator / heater matrix / etc.

If people want to use copper and it works for them then that's cool with me, I don't judge! :D I just try and avoid it myself unless there is a special reason to use it.



Thanks again everyone for all the help with this, I'll have to do a bit of waiting for the parts to arrive but I've got plenty of other things to sort out in the meantime.
Devil is in the detail (reading the reference in full). The copper t fitting having no direct contact with aluminium, and the coolant medium properties being far from that of native water, hence a relatively poor conductor. I've had these copper discussions on other car forums too - like don't use copperslip grease on head bolts into an aluminium block. Again theory is sound, but in practice I've somehow never had issues with using copperslip on head bolts on my engines, but others have had seized head bolts (Imp engines) by not using copperslip and only oil! I might think twice about copperslip on alloy wheel mounting surfaces though, given the salty nature of road spray. 8)

The Excel water pump leaks are seal-related, and the rad leaks are usually tank joint -vibration related, no aluminium issue here.
Peter K

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