[Mk2] [NA] Driving without thermostat

[TRDave]

My N/A has been leaking coolant for a while and last night i needed to get home in a hurry........!
The outcome was the car started to hesitate temp was ok but wen i stopped loads of steam and bubbling out of the back.
It sounded like a kettle being boiled.

i do get warm air thru the vents as long as its topped up but at speed it boils.
No mayo under cap no visible oil in coolant but i do get white steam from cold.
I'm totals skint as have lost my job due to cutbacks and still need to use my car.
It probably is HG isnt it????
Would running without thermostat help my cause at all ( besides poor mpg).

Wits end
Dave

[pbmr2]

the gasket could have failed directly into the water jacket and not into the oil (yet) so for now the cylinder is just boiling off your coolant.
that or your thermostat is jammed shut anyway and this is the problem.

the problem with these engines is that if they over heat too much (badly twice is enough) the head warps and the problem gets worse. it won't last long if it's steaming from cold. too much warp and the head can't be skimmed either.

mine went last autumn and i managed to limp it another 1500 miles just topping up the water with every drive. however i was changing my engine anyway so thought i'd do a test-to-distruction run with it and not fix the problem.

i could do around 30 miles before i had a problem but i was using very light acceleration and keeping the revs low in every gear, to try and give it a chance. running the heater on full hot all the time to aid cooling and unplugged the air con fan to make it run all the time.
also putting the clutch in down hills and not using fast roads like motorways and duel carriage ways.

taking the thermo out may help a little but the more times it over heats, the higher the chance of killing your engine is. but it could be the thermostat that is the problem. test it in a hot cup of water once it's out.

if you must drive it, top up the water before EVERY drive. run the heater on hot with the fans going. could take out the plug on the rad sensor to make the fan stay on at the front. maybe take off the plug to the engine bay temp sensor, that make the side fan run all the time, but this won't help much.
and drive it gently! light throttle and low revs in every gear. don't try to be in a hurry. tip toe along or you'll just kill it.

the longer you leave it, the worse the problems will be.

fixing it isn't that hard. on the super cheap you could get a HG for £35 and head skimmed for £30. new thermo for £9. do all the work yourself and job done. not the best way to do it, but it's better than driving it into the ground.

good luck

[foxy-stoat]

Where is it leaking coolant from?

Does your radiator fans come on when the temp goes up?

[TRDave]

Thanks for replys.
i have been doing exactly that limping around with the heater on.
What bits do i need to unplug to keep the fans going??

If it was the thermostat would i still get warm air?? as its hot most of time but sometimes goes cool until i rev it to bring the fluid round i presume.

As for where its leaking from ive no idea i need to borrow some ramps.
It left a puddle in the petrol station the other day and even though i had driven it for 12 miles the leaked coolant on the path was cold !

thanks
Dave

[foxy-stoat]

Unplug the sensor on off-side of the radiator, that will bring the fans on constantly. The heaters will blow cold when theres no coolant in the matrix.

When you have no coolant in the engine, it will overheat, depending on how many times and how long it overheats will depend on how long the head gasket will last. Taking out the theremostat wont really help you, unless its donald duck'd, see other post about checking.

If you have a stuck closed theremstat then it will make the engine overheat but to be honest, the loss in coolant and air in the system is the cause of your problems, if you continue to drive it then the head gasket will give up and cost you many hundreds of pounds to fix.

Find out where the leak is coming from and get it fixed, buy a new toyota theremostat (not very expensive) and fill with the proper coolant. Bleed the system properly and you will be fine. The leak can be from a number of places ranging from £1.10 and 5 minutes to fix to £150 and many hours to fix.

If you continue to drive it and you feel the heaters blow cold, then stop and let it cool down BEFORE you open the coolant filler cap before added coolant/water. If you open the cap when up to temperature then the water will instantly boil scolding your hand and shooting the cap half a mile in the air and across the car park!

If you top up before you set off each time and only drive it slowly for short periods then you should be ok. If you have knackered the HG then we'll expect to see this advertised on ebay with a pop'd engine like so many at the moment.

[TRDave]

Yikes

[foxy-stoat]

Post up your location, you may find a helpful local member take a look for you!

[alanmr2turbo]

this may sound stupid but ....... instead of trying to find a botch job to stop it over heating why not take a bit of time to find out where its leaking from and fix the problem?

Surely this would be a better solution?

[Mike N]

You need to carry out a cylinder leak down test which will confirm if the head or block is knacked, on a hot engine for better results.

You could also pressurise the coolant system to over 0.9 bar with the engine running, finally do a sniff test on the coolant system.

Most decent garages can do these tests fairly cheap. Up to an hours worth of labour for all of the above.