MK1 coolant hoses

Technical Area Engine, Transmission, Exhaust etc
2

Braved the cold weather and started cambelt/waterpump work on my 1997 MK1. The original hoses have done well, being nearly 22 years old but are clearly in need of replacement.

Not getting rid of the car any time soon so looking to replace with a similarly reliable product if possible. 

Not inclined to silicone but the only commonly available alternative, kevlar hoses seem to have a poor reputation.

Choice seems to be OEM or possibly IL Motorsports if these are rubber rather than kevlar reinforced. I am hoping, rather like the suspension bushes, they might be.

Can anyone point me in the direction of an affordable OEM 9 hose set for a MK1 1.6 1997 car or confirm that the IL Motorsports hoses are rubber, not kevlar reinforced and good replacements that faciltate use of original sprung fixings.

I also use vaseline when installing/reinstalling hoses. This always works well for me, suppressing corrosion whilst not degrading the hose material - anyone else use this or similar(for installing car coolant hoses I mean:-))?         

3

If it were me, genuine Mazda while they are still available. You’ll be kicking yourself in 5-6 years, when the cheap ILM hoses give up, and Mazda originals are scarce.

9-hose genuine Mazda hose set, 1.6, I priced up at £102 plus VAT (and before the usual discounts) from Autolinkuk, all in stock. I suspect Mazda counter prices won’t be far off (especially if you include postage). Bit more money than the £75 wanted for ILM’s unknown set (Chinese origin ? A lot of their parts are, and they might not even keep to the same supplier), but is it really unaffordable? Even if it cost more, I’d still opt for it. You’ve had hoses that have lasted 20-25 year thus far, and on a precautionary principle, want to change them out, for the next 20-25 years.

This is a steal:
https://treasurecoastmiata.com/i-22957651-90-93-new-oem-miata-complete-water-hose-kit.html

Can even get new clamps thrown in.

Never had to use a lubricant to fit a hose, but thinking about it, is there a reason not to use red grease? Need to find a use for the massive tub of it I picked up from a motor factors, other than the once in a while dabbing on brake caliper.

I am a big fan now of waterless coolant (Evans) after having the 1.8 converted to it. Took a bit to bleed it properly (maybe a difference viscosity to water+glycol). I like the idea of improved engine life due to absence of micro-cavitation, and piece of mind in having no pressurisation; nada, nothing. I can pop the radiator cap off (if I wanted to), engine redders, no loss of coolant. Coolant loss due to failed radiator cap thing of the past. Engine corrosion, thing of the past. Slimey crap on the inside of the hoses, thing of the past. Increased radiator life (stress fractures due to pressurisation?) Needs a bit of up front investment though; best part of £100 to do (cost can be reduced if two cars do it, as the flushing agent to remove water can be reused).

As for evidence of “similarly reliable products”, the only alternative that in the MX5 has any kind of similar 20 year+ track record are Samco silicone hoses; I have a recollection people were fitting these to 5 year old cars back in 1996. The Kevlar reinforced hoses have been around, say, 10-12 years, and as you indicate, have a patchy record. ILM hoses. Who knows. They don’t make the hoses themselves. They’ve invented “Genuine IL Motorsport” branding (ie. there are fake IL Motorsport parts). I notice where they are using some top German supplier, they can be quick to crow about that. So in the absence of that, I’m assuming China is the sourcing. China per se is not an issue; changing suppliers (and spec) is.

So OE Mazda.

4

I agree with Saz, I‘d only fit OE if was looking for performance, fit & longevity from new hoses.

5

Thanks for the reassurance with OEM hose choice. I was almost there, just toying with the idea of IL Motorsport and  waiting to hear back from them and MX5Parts to see what the hoses are made of and whether they can be fitted with the original clips. 

Seems that there are mixed opinions on vaseline. Clearly the original hoses are vulnerable to oil/petroleum based products, hence the issues with the softened heater hoses on the MK1/Eunos 1.8. My idea is just to use something to slow down the corrosion of the metal pipes the hoses are connected to, well the steel and aluminium anyway. Red rubber grease would probably work well but I’ve only got a small sachet or two - will probably use my silicone grease.

  

 

6

Waterless coolant would eliminate corrosion fears. But a good quality modern antifreeze contains corrosion inhibitors. One thing that I like about OE hoses is how they do develop stiction on the metal barbs.

7

Pleased to hear that the waterless coolant has worked for you - been installed for a while now IIRC. I would consider this but not at the moment. Just toying with the idea of replacing the crank seal. I seem to be lucky with the coolant in my cars - it stays looking fresh and has come out very clean on this job.

Yes, the hoses do seal well on the metal barbs. The corrosion problem for me is beyond the barb where condensation, sucked in water or perhaps a porous hose has introduced water into the interim environment between the barb and the end of the hose. Packing that with something that repels moisture and prevents corrosion, particularly on old, already corroded metal parts seems like a good idea.

Before I realised that Autolink have all the coolant hoses in stock I had emailed MX5Parts who have come back to confirm that they can source all the hoses but more expensive than Autolink who with the OC discount comes  to a tiny bit under £120 for all nine delivered. Have to give MX5Parts a chance to address this before ordering from Autolink. 

Thanks for the advice - I will struggle on at a snails pace with this job.       

 

8

Rhino,

At the risk of “Teaching Granny to suck eggs”, may I remind you the heater hoses that go through the bulkhead have caused grief in the past (given the age-related weakness) of the components the pipes are pushed in to.

It’s best to slice them long ways, and peel them off very carefully as thje pipes have gone AWOL or simply snapped behind the bulkhead panel.

I guess some red grease to insert the new ones would be a good idea. 

9

I think the main cause of corroding pipes is not contaminating external water splashes, but using old antifreeze and/or tap water.

You can probably get the hoses for more or less the same price from the local Mazda dealership. Well, I have.

10

Would be really interested to hear your experience as we have just bought all the kit to do the same to our 1.6 1990.  Have you considered / done the water re-route? Which we are also considering.

Any tips on maintaining the timing etc. would be gratefully received.

On the note of coolant ours is pretty grubby even though we have done a couple of flushes is there anything else that might clean it up better.  Interested to read about the non water based coolant.

 

 

 

 

11

Yes, had a look at these two hoses today and probably going to leave them unless I can break the seal on the copper easiiy - will have another go tomorrow.

As you say best method of removal is to slice them - that’s what I would do on anyone elses car. 

 

'Would be really interested to hear your experience as we have just bought all the kit to do the same to our 1.6 1990.  Have you considered / done the water re-route? Which we are also considering.

Any tips on maintaining the timing etc. would be gratefully received.

On the note of coolant ours is pretty grubby even though we have done a couple of flushes is there anything else that might clean it up better.  Interested to read about the non water based coolant.’

Hi Grumpy, that will be the short nose crank engine then. Don’t touch the main crank bolt unless you really have too - oil leak. If you so get a new woodruff yet, bolt etc and torque to the correct spec which is quite a lot lower than the long nose variety. 

Changing the belt will not mess up timing if you do it right, getting everything aligned on TDC. I would and in fact I am going to mark the CAS position with a pencil to ensure it goes back in exactly the right place - will mark it top and bottom to be absolutely sure. This is really the only thing that should cause issue with the timing.

Not sure why your coolant is getting grubby. Are you using a 50% concentration of coolant to distilled water? Is the grubbiness colour or particles. When changing coolant I flush the radiator - hose in top water flows out of the bottom and if good clean flow nothing to worry about. I also flush the engine through and clear as much out as possible before refilling. If there has been a period of neglect it may be that the seeds of corrosion have been sown and it will take a few coolant changes to rectify over time.

Have heard of the coolant re-route but would probably only consider if stressing the engine on track. For normal road driving conditions I don’t think I would bother.       

  

 

12

“Grubbiness” in the coolant sometimes due to the type of antifreeze used. HOAT antifreeze (the pink stuff) can look pretty murky peering through the radiator cap. Also, if the car has ever had Stop-Leak put it, you can end up with these particles in the system which sometimes seem impossible to shift through flushing.

Conversion to Waterless probably only worth it if you are also doing a cambelt/waterpump change at the same time. I can never understand these garages who drain a system, then refill with the same grubby looking coolant.

Lastly, there is Redline Water Wetter; there was a fad for this in MX5s about 10-15 years ago. If you don’t flush the system properly, water Weter precipitates out, and you end up with what looks like mud in the coolant. With Waterless, the main issue with water contamination is a loss of the whole point of this coolant (ie. back to pressurization etc).

13

I just change mine every year with a good quality antifreeze