Just purchased a 97 SC. Question about dissapearing coolant

Hi, just got ahold of my SC 1997. very sweet!! first thing i noticed tho was the thermostat was stuck open (temprature would drop when cruising on the highway.


I have now put in a new thermostat and toyota coolant which solved that issue. But now everytime i check the coolant level under the radiator cap its down a few inches and i have to top it up. At first i thought it may be due to air trapped and needed bleeding.

I dont believe its a headgasket or head issue, no coolant in oil, no air bubbles or temprature issues.

I have noticed the expansion tank doesnt seem to change level, So i dont believe its spitting/sucking coolant back into the system.

Has anyone had this issue?

Welcome mate, when you bleed the system make sure you have both front and back heaters on and if you have no probs with overheating I wouldn't touch the rad cap just keep the bottle up to speed. If the level gets down you will get a light on the dash to tell you.
You've  done well changing the thermostat it's in a mongrel of a spot

Cheers AussieQ.

Your not wrong about that thermostat located under the turbo!! what a pain!

Im starting to wonder if my mystery coolant loss is from the thermostat housing, and merely evaporating away from the heat for the exuast/turbo - hence no drips on the ground.

All i know is im losing a small amount of coolant after i changed the thermostat. (have topped up maybe 20 times so far from short trips to work and home each day. ABit scared to do a big long run tonight incase it keeps using coolant.

Any problems starting?

Any steam from the exhaust on start up?

Very rare for oil and water mix with these engines more likely a crack in the cylinder head water ways that leaks into the cylinder.

However check all hoses for leaks first before going down the $$$ route.
Did you fit a new O ring with the thermostat?

Seems alright starting. The motor has done 60,000km feels pretty tight and smooth still.

Hard to tell about the steam, its so cold down here in Tasmania at the moment, but i smelt the exuast and it didnt seem to have that sweet coolant smell to it, but the amount of coolant im losing isnt alot.

Yep new thermostat o ring seal. Noticed some sort of hard copper looking buildup on the thermstat housing, couldnt remove, but put the thermstat andseal in anyway and tightened it up. Perhaps its releasing coolant under pressure from there, altho no tell tale signs in that area when looking at it.

Could well be a tiny small BHG/cracked head. Not to impressed since i only just buaght it a week ago, and no warrenty came with it

No leaks in the radiators? Check for any small puddles of coolant on the ground 10-20min after you shut the engine down, pressure will be at it most then. Do all the heaters work? If not then you may have air lock.

Yeah well done on the thermostat. Did you get to it through the wheel arch? I did mine a few years back, lot's of cursing!

Thanks for the suggestions there srburnsy, No leaks at all, all heaters working well.

But i have done a few long trips of about 300km and checked the coolant, and its still only a few inches down frmo the filler neck, So it looks like its not consuming coolant afterall.

It must spit out a little coolant everytime i top it up, probably from pressure, and it must fail to suck it back in to the radiator. I better get a new radiator cap (even tho the one on there now looks perfectly find).

Also cant understand why the overflow bottle hasnt changed its levels at all. *scratches head*

oh well main this is i dont have to worry about cracking a head due to lack of coolant.

Cheers all

Had a similar issue losing small amounts of coolant - no obvious leaking from anywhere including rads & heater matrices, no sign from the exhaust and no water in the oil (or oil in the water).

Was topping it up regularly but then went on a long run and noticed the temp guage climbing more than usual.

Pulled over at a service station just in time for it to hit the red - then blew all the coolant out through the overflow tank.

Looks like I hadn't been topping up enough.

I'd tried all the usual stuff, so suspecting something sinister (like a cracked head), I had the garage take a look. The only thing they could find was a small but noticeable pressure build in coolant using a gauge in place of the filler cap.

Stripped head off and found some discolouration in No.3 cylinder (suggesting a leak) but no obvious tracks on the cylinder head.

Had head skimmed and pressure tested then replaced gasket and put back together. The system still appeared to be consuming coolant until they gave the head bolts a further 1/4 turn. Now runs well - have done several long runs (500 miles) and no probs/no coolant usage.

Well hi from down here in n.z, ive a 98 sc done 140000km and have pulled both radiators and had flushed and pressure tested then replaced the water pump and fitted a hi flow thermostat then put all back together and still got a mystery water loss of about a litre?? fitted a manual temp gauge that sits about 200?? good or bad??.do you think i should give the head bolts a little crank may-be??.Thanking you smiler..