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Long story short, during the service I damaged these two pipes (Pictured).

I think the one connected to the water pump is salvagable (You can see the bit that snapped off) so I am not too concerned about that. Is it possible just to bung is up? It doesn't seem like it does much. What I am concerned about is that fact that one of the pipes coming from the heater travels directly under the headers. I googled and people re-route this so that it goes outside of the headers, I may as well do this since the pipe is damaged. Has anyone done this? Experiences? Other suggestions? Deleting the lines is also not out of the question if possible as I don't care about the heater.


I tried searching the forum for these particular re routes and deletes but couldn't find anything.

PM sent

Opps,
Ok, the heater pipe that your pointing to should not be blocked off, get another pipe or repair that one.
The heater system is a major part of the cooling system and as such should be left alone and working.
To rid yourself of the little pipes, yes you CAN bypass them or blank them off as this picture shows

but to be honest your going to need them next winter, the little pipes work in with the fuel system for starting and as such
when it gets down to 2 or 3 degrees your going to wish they were still connected.

The good thing here is that the 1.6 and the 1.8 pipes and fitting are the same so shouldn't be too hard to get some in Brissy.

Terry

I see this is six weeks old, so maybe the problem has been solved, one way or another. If not, perhaps the following may be helpful (or not!).

My racecar runs no heater, and doesn't seem to miss that 'major part of the cooling system' even though it runs a standard MX5 radiator. Unless you are using the heater to heat (and therefore cool the coolant passing through it) all it is doing is a) providing more coolant to be a bigger heat sink for the heat generated, and b) circulating said coolant. If your cooling is that marginal that the heater makes a difference, you need to look more closely at the efficiency of your overall cooling system including the radiator and the integrity of the ducting/undertray. Ironically, I am looking at reinstating a heater circuit on the racecar to provide screen demisting via a miniature heater core.

However, when people talk about 'coolant reroute', they generally mean blanking off the MX5 coolant outlet (closest to the radiator), and taking the coolant to the radiator from the rear of the cylinder head. This is where the outlet is in FWD installations of the B6/BP engines, and our MX5s can suffer from overheating in the region of No4 cylinder - especially if they are high power cars - as a result of poor coolant flow in that area. Thus the heater outlet in that location, which takes coolant from this area to the water pump via the heater (regardless of whether the heater is 'heating' or 'cooling') which is what I think TCR is referring to. So, if you blank off that outlet, and the inlet at the water pump, you may have a problem (I will let someone else say for sure whether, and how big, that problem may be). Bottom line, if you blank off the heater, keep the coolant flowing from the back of the head to the water pump.

Likewise, I have no idea what might be the benefit of circulating coolant through throttle bodies or manifolds, but cold starting will not be one of them. Coolant at or near ambient is no better than ambient, and since there is little on there that is heating significantly the coolant will not be cooling much. Again, my racecar has these all sealed off and does not seem to miss this coolant, but I would be happy to be convinced of the benefits for a road car (intake de-icing?). However, if you don't know what you are doing, or the consequences, probably better to play it safe. If you have blocked them off already, please let us know how you go.

greenMachine wrote:I see this is six weeks old, so maybe the problem has been solved, one way or another. If not, perhaps the following may be helpful (or not!).

My racecar runs no heater, and doesn't seem to miss that 'major part of the cooling system' even though it runs a standard MX5 radiator. Unless you are using the heater to heat (and therefore cool the coolant passing through it) all it is doing is a) providing more coolant to be a bigger heat sink for the heat generated, and b) circulating said coolant. If your cooling is that marginal that the heater makes a difference, you need to look more closely at the efficiency of your overall cooling system including the radiator and the integrity of the ducting/undertray. Ironically, I am looking at reinstating a heater circuit on the racecar to provide screen demisting via a miniature heater core.

However, when people talk about 'coolant reroute', they generally mean blanking off the MX5 coolant outlet (closest to the radiator), and taking the coolant to the radiator from the rear of the cylinder head. This is where the outlet is in FWD installations of the B6/BP engines, and our MX5s can suffer from overheating in the region of No4 cylinder - especially if they are high power cars - as a result of poor coolant flow in that area. Thus the heater outlet in that location, which takes coolant from this area to the water pump via the heater (regardless of whether the heater is 'heating' or 'cooling') which is what I think TCR is referring to. So, if you blank off that outlet, and the inlet at the water pump, you may have a problem (I will let someone else say for sure whether, and how big, that problem may be). Bottom line, if you blank off the heater, keep the coolant flowing from the back of the head to the water pump.

Likewise, I have no idea what might be the benefit of circulating coolant through throttle bodies or manifolds, but cold starting will not be one of them. Coolant at or near ambient is no better than ambient, and since there is little on there that is heating significantly the coolant will not be cooling much. Again, my racecar has these all sealed off and does not seem to miss this coolant, but I would be happy to be convinced of the benefits for a road car (intake de-icing?). However, if you don't know what you are doing, or the consequences, probably better to play it safe. If you have blocked them off already, please let us know how you go.

Only posted it today

Thanks for the insight. I haven't decided on what I'm going to do yet. I'm thinking of re-routing from the heater outlet, around to near the intake and back to the water pump. I really don't like the idea of it traveling under the headers. But this way will require some modification to the pipe that connects to the coolant pump and that's extra effort I don't know I'll have time for. How do you have yours set up (Pictures?)

Ooops! Must have looked at your join date .

I have a full coolant reroute, no heater; it runs from the back of the head, over the exhaust, and around the front of the head to the radiator inlet (thermostat in back of head, outlet at front of head blanked off). Therefore there is no pipe or connection from the back of head to heater to water pump. Probably uses a FWD thermostat housing, but I don't know for sure. No photos atm, sorry.

There is an alternative which takes the coolant around the inlet side, but mine is hot side.

If you are going to reroute anything, I suggest you look closely at a full coolant reroute (with or without the heater), especially if track duty is expected, or a turbo is planned (definitely if both).

Search on here, the big board (Miata.net), or Miataturbo.net for details. Some vendors sell kits, check out forum sponsors.