Miata Q - change the coolant hoses at around 130k?

The Miata (1995 NA) needs fresh coolant anyway as the current stuff in there is only good for about -10F. If we ever get a proper winter here that is a bit marginal, so it's time.

The original plan was to flush the cooling system and replace the coolant with some fresh Prestone, then replace the thermostat with a new OEM one at the same time "while I'm in there". However some of the coolant hoses look a little old - not in "bad, change immediately" condition, just "well used" so the thought occurred to me to replace them with some fresh hoses, maybe even some silicone hoses. Which reminds me, I need to check the two hoses near the firewall, they might be definitely due for replacement.

Thoughts? Comments? Just Do Eet?

Oh, any recommendations for silicone hoses?

Consider a coolant reroute.

Yes.

Change $40 worth of coolant hoses in an hour or so today, and save spending the whole day and hundreds of dollars changing a head gasket later.

RossD wrote: Consider a coolant reroute.

Relevant to my interests.

I'm getting ready to order my reroute kit, what are the other parts I should consider changing while doing it? The two heater core hoses, but anything else?

The job looks like a PITA, so I'd like to get everything I can while I'm in there.

RossD wrote: Consider a coolant reroute.

My understanding was that it's not really necessary on a well maintained NA with a stock engine, or am I off on this?

If your car has the early style, two piece lower hose, change it to the later style one piece hose.

Or the FM silicone lower hose Then you're future proof for a turbo.

The radiators are much more failure-prone than the hoses, BTW.

As for coolant reroutes - a stock NA shouldn't need one for street use. If you do, you're trying to address the symptoms of some other failed part.

I had a 96 with 105k miles. One of the hoses at the firewall failed about 20 minutes after the new owner took delivery of it. He was driving it home from my house in Connecticut to his in Maryland. Neither one of us was happy and I drove out and did the roadside repair for him.

Change them all.

As for me, that water outlet gasket is leaking (so I'll be back there anyway)and I'm going to be tracking the car in the OK heat.............add in future turbo plans, I figure I might as well go ahead and do the reroute kit.

Keith wrote: Or the FM silicone lower hose Then you're future proof for a turbo. The radiators are much more failure-prone than the hoses, BTW.

It's already got a new radiator not too long ago - the PO managed to crack the top tank when changing the timing belt. Unfortunately it's a stock type replacement with plastic tanks...

Keith wrote: As for coolant reroutes - a stock NA shouldn't need one for street use. If you do, you're trying to address the symptoms of some other failed part.

It's not running hot or giving out any suggestion that there is a problem, but I'd rather keep it that way now.

I'd go ahead and change them. It's actually quite easy - except for that coolant plug at the rear of the motor... That one is a biatch.

I'd advise sticking with OEM hoses and OEM constant torque hose clamps. Silicon coolant hoses don't seem to last as long as high quality OEM rubber. Also, with the silicon coolant hoses, you usually need to use some kind of worm clamps which loosen after a few heat cycles requiring constant maintenance. Youtube has a good video illustrating why the OEM style spring clamps are better at sealing if you want to research that further.

On my 20 year old Miatas, I've never had a hose fail. Thats not to say they wont, but....

Joey

Keith, do you think the coolant reroute is a good idea for a stock-motored track Miata? In concept it seems like 'the right thing' but I don't really like all the extra hose and fitment, to be honest. But if it really is the right thing to do...

robert

Is there something I am missing on why the 2 piece lower hose is a bad thing?

If so, is it legal to change within STS rules?

Nope, timing belt was done 10k ago. So at least I'm good on that one.

I'll have a good look at the firewall ones and probably that big plug on the back of the head before I get ordering.

robertcope wrote: Keith, do you think the coolant reroute is a good idea for a stock-motored track Miata? In concept it seems like 'the right thing' but I don't really like all the extra hose and fitment, to be honest. But if it really is the right thing to do... robert

It's not the fix-all cooling upgrade some people think it is - a good radiator and fan setup makes a bigger difference in my opinion.

Apexcarver wrote: Is there something I am missing on why the 2 piece lower hose is a bad thing?

A one-piece unit has half as many failure points. Plus those steel chunks in the middle seem to like to rust.

the only hose failure I ever suffered in 18yrs of miata ownership covering 14 miata was the nipple blocking hose on the back of the head. Change that one periodically. They dry out and blow out the end.

Isn't that the one that's only on 1.6 cars?