boiling coolant

jim · 11-23-2009, 03:26 AM

Help!! I have a 1992 supra turbo. Since having the HG replaced (for the second time) The engine runs hot, does not overheat, and when its turned off the cooloant in the overflow tank is boiling. the new Hg has been checked and seems to be ok. The car is frequently low on coolant. Have tried block sealer no help. Anyone have any suggestions.

MA70-3.0GT · 11-23-2009, 02:10 PM

Couple of quick Q's. When you had the gasket replaced did you also get the head skimmed & both it & the block tested for warpage? If the car has ever overheated really badly it may have sent the head too far out of true to be skimmed back (or possibly it's been skimmed that many times it's made the compression ratio too high).

If both the block & head were true & within spec (and I assume you fitted a standard composite HG, metal ones require further finishing work to head and block) then it could possibly be that the head was not torqued down to the correct figure, which is around 70lb as opposed to toyota's incorrect 58lb.

The first thing I would say to do though (provided block tests are coming back as no gasses in the coolant, if there are then it's a definite HG issue. If you haven't had a block test this is first on the list) is to do a search on "Burping" the heater core as this can cause BHG like symptoms due to airlocks which are hard to get rid of without following the correct procedure. From the "boiling" overflow tank though (more likely air being forced past the pressure cap making it bubble & appear to boil) I'd hazard that the HG is leaking combustion gas into the water jacket.

Hope it turns out to be the heater for your wallet's sake, best of luck & let us know how you get on.

jim · 11-27-2009, 11:19 PM

I had the systemed 'burped" and removed the theromstat. Car drives smoothly and has stayed quite cool. No boiling in the overflow. We have noticed however a gurgiling water noise on excelleration. Other than that its running great. Is this something to be concerned about and if so any suggestions.

cre · 12-09-2009, 04:13 AM

The gurgling indicates air in the coolant system. Running without a thermostat is not a good idea (it's a very bad idea actually).

11-23-2009, 03:26 AM	#1
jim Stock Join Date: Nov 2009 Location: nj Posts: 2	boiling coolant Help!! I have a 1992 supra turbo. Since having the HG replaced (for the second time) The engine runs hot, does not overheat, and when its turned off the cooloant in the overflow tank is boiling. the new Hg has been checked and seems to be ok. The car is frequently low on coolant. Have tried block sealer no help. Anyone have any suggestions.

11-23-2009, 02:10 PM	#2
MA70-3.0GT 12psi boost Join Date: Oct 2009 Location: Crewe, England Posts: 356	Couple of quick Q's. When you had the gasket replaced did you also get the head skimmed & both it & the block tested for warpage? If the car has ever overheated really badly it may have sent the head too far out of true to be skimmed back (or possibly it's been skimmed that many times it's made the compression ratio too high). If both the block & head were true & within spec (and I assume you fitted a standard composite HG, metal ones require further finishing work to head and block) then it could possibly be that the head was not torqued down to the correct figure, which is around 70lb as opposed to toyota's incorrect 58lb. The first thing I would say to do though (provided block tests are coming back as no gasses in the coolant, if there are then it's a definite HG issue. If you haven't had a block test this is first on the list) is to do a search on "Burping" the heater core as this can cause BHG like symptoms due to airlocks which are hard to get rid of without following the correct procedure. From the "boiling" overflow tank though (more likely air being forced past the pressure cap making it bubble & appear to boil) I'd hazard that the HG is leaking combustion gas into the water jacket. Hope it turns out to be the heater for your wallet's sake, best of luck & let us know how you get on. __________________ '89 MA70 Supra GT aero 3.0turbo JDM, Rebuilt motor, K&N intake, 3" stainless turbo-back. New turbo and braided line kit... '89 Honda NC27 400, NC23 cams, open pipe, PC36a shock & possibly Showa USD forks... '83 Yamaha 29R XJ750E-II, number 69 off the line, only runner in the country? Original except Koni shocks '95 Honda PC26 CB500R, Winter hack, hateful, trying to sell it I'm not paranoid, they really ARE after me!!! Last edited by MA70-3.0GT; 11-23-2009 at 02:15 PM.

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Heater Union (Coolant Leak)	slader99	MKIII Supra	11	12-28-2009 12:29 AM
Funky engine coolant issue	shirkinator	Non-Generation Specific Questions	1	06-22-2009 08:37 AM
coolant on top of piston	sevenmgte	MKIII Supra	8	05-02-2008 02:34 AM
Coolant leak issues	D_Train	MKIII Supra	1	03-15-2007 04:30 AM

11-27-2009, 11:19 PM	#3
jim Stock Join Date: Nov 2009 Location: nj Posts: 2	I had the systemed 'burped" and removed the theromstat. Car drives smoothly and has stayed quite cool. No boiling in the overflow. We have noticed however a gurgiling water noise on excelleration. Other than that its running great. Is this something to be concerned about and if so any suggestions.

12-09-2009, 04:13 AM	#4
cre Toyota Racing Development Join Date: Apr 2007 Posts: 5,038	The gurgling indicates air in the coolant system. Running without a thermostat is not a good idea (it's a very bad idea actually).