Okay so I’m new here and only just got my first mx5 2 days ago however I’ve come across a cooling issue. When I take the car out on long runs the heat gauge goes up over the 3/4 mark and I get worried the engine is about to blow up on me. I’ve ordered a new radiator, thermostat, hose kit, and some new antifreeze but as I was researching it I came across a coolant reroute option. I couldn’t find any complete reroute kits for my mk2 10th anniversary edition mx5 and wondered if the upgrade is really worth doing for normal road use? The previos owner said he never had a cooling issue but he hadn’t been using it for while before selling it. Maybe something packed up during that time but who knows.
As I said I’m new here (my first post yiy) so any advice would be much appreciated 
Thank-you :v
also it wont let me change my avatar and I accidentally set it to this, good god this is embarrassing…
also it wont let me change my avatar and I accidentally set it to this, good god this is embarrassing…
Although it may seem a bit odd to have cooling pipe directly under the exhaust manifold it doesn’t usually cause a problem if everything else is functioning correctly. Change the items you have ordered and try it again. ( my money would be a radiator problem). My opinion is that , under normal road use, a bypass kit is unnecessary. None of the racing series use them and overheating is not an issue. Let the forum know how you get on.
Welcome to the club.
As far as I can tell, the reroute is good for when you have constant higher ambient temperatures and your are putting the engine under a lot of stress, such as endurance racing. For road use in the UK the reroute is overkill and will probably be detrimental to the engine. I would agree with tfrgeen, fit the parts you have order, which is logical, and let us know how you get on. When I first got Mixie5 I had the same issue. A replacement radiator and thermostat fixed the issue.
Welcome to the club.
As far as I can tell, the reroute is good for when you have constant higher ambient temperatures and your are putting the engine under a lot of stress, such as endurance racing. For road use in the UK the reroute is overkill and will probably be detrimental to the engine. I would agree with tfrgeen, fit the parts you have order, which is logical, and let us know how you get on. When I first got Mixie5 I had the same issue. A replacement radiator and thermostat fixed the issue.
I’ve had an overheating issue with my MK2 for a while now - ever since MX5 Works in Leighton Buzzard serviced it - not had time to get it to the garage I now use back home as only have a Saturday to do this and I’m only doing about 50miles a week in her just now & have been since January.
Overheating doesn’t seem to happen when it’s cold outside, but certainly does when I’m gunning it for a good few miles (faster than legal for say 10 M-way miles) or climbing hills - lot of them around the West coast of Scotland or when it’s hot, also does it if slow driving eg climbing up levels in a multi-storey car park. Banging on the heater brings it back down so I suspect (just my guess) there’s an issue with the routing of the pipes or the fan not working just as well as it should be
Having spoken to the mechanic in the garage I now use and he says first thing they’ll do is a pressure test on the system, then “throw a thermostat at it” I’m considering getting both the thermostat & the water pump done at the same time - although these where previously done in the service (allegedly).
The fan does come on and seem to be working OK and there are no cold spots on the radiator - so therm/water pump seem most likely cause, if it’s not the fan or routing of pipes.
Was thinking of getting one of these http://www.ebay.co.uk/itm/like/152558382604?ul_noapp=true going to post the link in another part of the forum - just wondering if anyone has one / has used one? Pics & video seem to show it as a very useful diagnostic tool & a lot better then the diode one. Be nice to go back to the mechanic and say it’s “insert cause” and then let him see/use the diagnostic tool & his own experience - I trust this guy.
Thanks for the help guys, I’ve decided to install the new parts I already bought and see if that fixes the cooling issue. The reroute will be left out for another day (maybe), I’ll update this post once I’ve installed the parts to let you guys know if it cured it. Thankyou
A few years back I had an overheating problem when driving at speed or climbing long sloping hills, but it was of my own making. I had designed and fitted a new grill, made from aluminum, in front of the radiator. I hadn’t left enough spaces in the new grill to let the air through to the radiator. Removing the grill very quickly proved this was the case as the engine didn’t get over heated with the grill removed. After some modification to the new grill all was well with the engine temperature.
Irrespective of the grill that is fitted try running it for a short while to see if the engine temperature still rises or not. Do not be tempted to use the car without a grill for days on end as a grill protects the radiator from stones etc to some extent.