HELP- Cooling issues Mk1 1.6. 1990, Jap import.
Discussion
Hi All,
My wifes MX5 keeps overheating. Its 1990 1.6 Jap import- standard.
It started over heating in traffic, so noticed that the rad was full of dirty, mucky water (not oil!) so I drainned the raditor. I also noticed the fans where not switching on to cool the rad- so I relplaced the Thermostat- however only one comes on. Is that correct?
Anyway it still over heats- there is no air-lock.
Obviously we switch on the Air-con to get both fans on.
I am now thinking the following should be replaced:
A) Rad Cap
B) Radiator
Do you cars stay cool with out the need of cooling fans for say, 3 minutes on tick over.
Seems like the rad and fans can barely keep the car cool.
My wifes MX5 keeps overheating. Its 1990 1.6 Jap import- standard.
It started over heating in traffic, so noticed that the rad was full of dirty, mucky water (not oil!) so I drainned the raditor. I also noticed the fans where not switching on to cool the rad- so I relplaced the Thermostat- however only one comes on. Is that correct?
Anyway it still over heats- there is no air-lock.
Obviously we switch on the Air-con to get both fans on.
I am now thinking the following should be replaced:
A) Rad Cap
B) Radiator
Do you cars stay cool with out the need of cooling fans for say, 3 minutes on tick over.
Seems like the rad and fans can barely keep the car cool.
Sounds like a blocked radiator - this is a fairly common problem with MX-5's.
With the engine hot, try feeling the front face of the radiator to see if there are any cold spots.
You could try using a radiator flush and replacing the fluid but my money would be on a terminally blocked radiator.
It might be possible to remove the rad and back-flush it using a hose-pipe but usually once they get to this stage it's pretty much dead.
With air-con there are 2 fans. The off-side one only comes on with the air-con.
With the engine hot, try feeling the front face of the radiator to see if there are any cold spots.
You could try using a radiator flush and replacing the fluid but my money would be on a terminally blocked radiator.
It might be possible to remove the rad and back-flush it using a hose-pipe but usually once they get to this stage it's pretty much dead.
With air-con there are 2 fans. The off-side one only comes on with the air-con.
My radiator blocked too.
They're pretty cheap from mx5parts so I'd just throw a new one in.
Of course, for the pittance they cost it may be worth trying a new radiator cap first as I did to no avail.
For what it's worth, the symptoms on mine were slightly different as it would only get warm when travelling at continuous high speed.
They're pretty cheap from mx5parts so I'd just throw a new one in.
Of course, for the pittance they cost it may be worth trying a new radiator cap first as I did to no avail.
For what it's worth, the symptoms on mine were slightly different as it would only get warm when travelling at continuous high speed.
Mine overheated and boiled up, and upon investigation I found that not only was the rad full of brown sludge with flakes in, but that these flakes had clogged up the waterpump and also completely blocked the 2 small pipes that exit from the bottom of the thermostat housing that carry the coolant around the engine when the thermostat is closed. In the end I had to drill these out to clear them.
When you fit the new rad, thermostat and rad cap make sure you check that these pipes are clear, might be worth fitting a new waterpump also.
When you fit the new rad, thermostat and rad cap make sure you check that these pipes are clear, might be worth fitting a new waterpump also.
re water pump. I expect rad probably sprung a leak at some time and a previous owner "fixed" it by putting rad-weld in it. That along with using plain tap water rather than a coolant mix would explain the brown sludge.
I'd suggest the following:
Use a rad flush agent as instructed.
Remove the rad and back-flush it through with a hose-pipe.
Remove the thermostat then try to flush the block through with a hose too.
Refit the radiator.
Fill with plain water and run up to temp.
Check for leaks.
Check for cold spots on the rad.
If there is a cold spot, replace the rad.
If the rad seems fine, go for a thrash to make sure the water gets a proper high-pressure run through the system.
Drain the coolant again before it cools right down.
Check the thermostat housing for sludge in the pipes.
If it's clear then refill with the proper coolant/distilled water mix.
If it's still sludged up, use a coolant flush again, this time go for a bit of a run with it in the system (don't thrash it though) then go through the process again.
I'd suggest the following:
Use a rad flush agent as instructed.
Remove the rad and back-flush it through with a hose-pipe.
Remove the thermostat then try to flush the block through with a hose too.
Refit the radiator.
Fill with plain water and run up to temp.
Check for leaks.
Check for cold spots on the rad.
If there is a cold spot, replace the rad.
If the rad seems fine, go for a thrash to make sure the water gets a proper high-pressure run through the system.
Drain the coolant again before it cools right down.
Check the thermostat housing for sludge in the pipes.
If it's clear then refill with the proper coolant/distilled water mix.
If it's still sludged up, use a coolant flush again, this time go for a bit of a run with it in the system (don't thrash it though) then go through the process again.
Edited by MX-5 Lazza on Tuesday 12th August 18:48
Blimey, it's not difficult - I've just put a new belt on a recon engine having removed every pulley in sight, took about 10 minutes - set bottom pulley so the notch is upwards, set cam pulleys so they're pointing I and E upwards, put belt on and get 19 teeth across the top between the pulleys' I and E marks (inclusive).
Rotate it all then check it still lines up.
It's really very easy to do, you're only ligning up 3 things.
Rotate it all then check it still lines up.
It's really very easy to do, you're only ligning up 3 things.
Edited by anonymous-user on Friday 15th August 15:21
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