Oh no, not another coolant reroute...
 

Well, eh, yes, sorry.

I have an 1998 NB 1.6 which will shortly be receiving a 1.8 VVT with turbo. OK. So when cleaning up the donor engine, I also swapped the head gasket for the better flowing one and even re-opened some holes to make sure cylinder 1 get some, too. So far, so good. Next, I did the cheapest coolant reroute ever, swapping the thermostat and thermostat housing from the front to the rear and blocking the fron off with a blanking plate. I eliminated the feed to and from the interior heating, since it rarely freezes here and when it does, I stay in bed with the blankets over my head. No need for heating in the MX5. But last week my car failed MOT (with the old 1.6 still in it) because the heater didn't work. Now this was a blower issue and easily solved, but I learned I need to have a functional warm window defrosting solution to pass MOT, regardelss of my own actions during cold days. Hmmmm... So should I spend a lot of money? Heck no, I'm Dutch, we're cheap. So searching the www I found this Audi part;
https://ae01.alicdn.com/kf/HTB1l93li...49-1K0-121.jpg (pt.no. 1K0121049)
Which I could splice into the hose running from the rear exit of the cooling circuit to the front. But then the heater connection is after the thermostat. Now I don't think that is a problem, but I also found this part:
https://cdn.pkwteile.de/uploads/360_.../h-preview.jpg
Which I could also splice into the hose, and remove the original thermostat. The only downside to this item is that it has 20 mm connections, not 28.

Please post your thoughts. I know I can just buy a reroute kit, but that is not the point of this post.
Cheers,

Hugo

You've made quite a mess.

I would drill and tap two locations and add the two correctly sized hose barbs if there was no easier way. But I don't know what you have done already.

Condensation and windowfrost is a bitch during normal dutch winters so unless you don't drive in winter you should have it anyways..
- You can make your own spacer if you have more time than money.
- On the 1.6 you can fit a hose from the cursed waterplug and loop it into the heater core.
- On the VVT remove the block off bolt in the head next to the thermostat. Fit a 90 degree fitting (thread is m12x1.5) and loop that into the heater core. Normally you can put your coolant sensor in here but that now needs to go somewhere else.

These options probably cost less than that remote thermostat and you don't create a restriction. You will get sup-par performance in the heater but you already said that you don't care about heating performance.

With adapters to change hose sizes you could intercept the water flow going to the oil warmer and back.