G_Wheezy

So I'm having a problem with my miata with a weird coolant leak. I have a 1990 with a 1.8L swap and whenever I get on the gas and go through the gears I get a coolant leak that leaks onto my belts, causing squeal. The coolant looks clean, oil on the dipstick looks clean as well. My first guess is a bad waterpump, but I'll take any other suggestions. Thanks.

deezums

iTrader: (3)

I suggest you fix the leak.

G_Wheezy

Thanks man!

festersays

iTrader: (3)

Water pump, thermostat housing, hoses. Take a look at those in whatever order you please.

shuiend

iTrader: (24)

Is it leaking onto the outside belts or the timing belt? If you do not have a reroute and the front water neck removed I would check there for leaks first if on just the outside belts. Much easier and faster to get to then pulling everything off to get to the water pump.

Itty

When I first got my car it was leaking coolant onto my timing belt from those tiny hoses under the water neck. One goes to the intake, the other goes down to the mixing manifold (I think).

If that is the case, you can usually make it leak worse (i.e. confirm location) by yanking on the hoses near the clamps.

G_Wheezy

Thanks for the responses. It's leaking on the front belts and can be seen on the radiator fans. It also pools up in the plastic undertray if that says anything. I have pics of it on my introduction thread, let me see if I can copy them over here.

stefanst

iTrader: (1)

Those pictures do indeed confirm that you sir have a coolant leak!
Unfortunately all they can tell you about the location is "front of the engine" and you already knew that.

olderguy

iTrader: (19)

Radiator

G_Wheezy

I'll start looking at the hoses, thermostat, and water pump then. I'll probably just replace the cheap stuff that should probably be refreshed anyway and go from there.

Girz0r

iTrader: (1)

Does it leak only when you're on the throttle or is it leaking when the motor is fully warmed up & the coolant is pressurized?

I'd try to wipe & dry everything you can, let it run & idle in the driveway up to temp and see if it starts dripping.

I had a pin sized hole in the coolant hose coming off of the throttle body around to the water neck. Couldn't find where it was coming from until it left residue on the hose.

G_Wheezy

It could possibly be leaking when it's warm and pressurized, but I've never noticed it. It's only when I get on it that it gets onto the belts and causes squealing, and only then when I notice it dripping onto the ground. I've not seen puddles when driving it normally from work to home. I could try wiping everything down and seeing what happens.

gooflophaze

Go rent this tool.

OEM/Radiator and cap test kit 27065 - Read Reviews on OEM #27065

advance/auto loans it out with a deposit, last time I ended up buying it. Any weeping leak turns into a **** stream. Any small cracked hose, any radiator matrix crack.

EErockMiata

I would just replace all of the hoses and the radiator personally... those are cheap and at this point even the nb2's are pushing 15 years old. It could obviously also be from the mixing manifold or the waterpump gaskets... but those typically get replaced often enough (read: TB/WP job every 60k) that those leaks are rare.

jmann

Do what gooflohaze said. Put pressure to it warmed up so the stat is open and the motor shut off, you well find it easy.

G_Wheezy

I'll definitely do that, thanks.

EricJ

OEM Radiator? What color is the top?
Green or Black.
Green, replace the radiator.

Crimson

I had a leak (after putting a 1.8 in my 90) exactly like you're describing. Mine was coming from the hose that has a 90 degree bend right next to the PS pump pulley. Leaked right onto the belts under load and drove me nuts on startup. Didn't find that's where it was coming from until I took it apart to change the belts.