jamie c Posted November 25, 2021 Report Share Posted November 25, 2021 I have done it twice and o rings not pinched and thermostat in place properly. I have dye in coolant system to trace leaks. I have trued up the bottom of the thermostat housing on a flat plate with 300,400 and finally 800 sand paper. The top of the engine where the thermostat housing is bolted looks good no pits but its not perfectly smooth because due to its cast aluminum. The hoses are not leaking. I can see the thermostat opening when I drive as themperature on temp gauge drops just past 80 degrees and then continues to warm up. Can anyone tell me if I should be using a sealant on the housing to help seal for leaks? Quote Link to comment Share on other sites More sharing options...
mike_sekinger Posted November 25, 2021 Report Share Posted November 25, 2021 You should not need to apply any sealant. I have never applied sealant to the thermostat housing on any of the engines that I have build. I typically apply a small amount of rubber grease to the o-rings, just to hold then in their ring grooves when fitting. If you are having a proven problem there, then I would be looking at the o-ring not being correct thickness. Where did you source the o-rings? Quote 1996 Esprit V8, 1998 Esprit V8 GT, 1999 Esprit S350 #002 (Esprit GT1 replica project), 1996 Esprit V8 GT1 (chassis 114-001), 1992 Lotus Omega (927E), 1999 Esprit V8SE, 1999 Esprit S350 #032, 1995 Esprit S4s, 1999 Esprit V8 GT (ex-5th Gear project), 1999 Esprit V8SE ('02 rear) 1999 S350 #002 Esprit GT1 replica Link to comment Share on other sites More sharing options...
jamie c Posted November 25, 2021 Author Report Share Posted November 25, 2021 I’m in canada, I use parts from JAE. Quote Link to comment Share on other sites More sharing options...
mike_sekinger Posted November 25, 2021 Report Share Posted November 25, 2021 Well JAE are excellent, so should be supplying the right o-rings. Could it be that the o-ring is falling out of position on installation (being upside down)? Quote 1996 Esprit V8, 1998 Esprit V8 GT, 1999 Esprit S350 #002 (Esprit GT1 replica project), 1996 Esprit V8 GT1 (chassis 114-001), 1992 Lotus Omega (927E), 1999 Esprit V8SE, 1999 Esprit S350 #032, 1995 Esprit S4s, 1999 Esprit V8 GT (ex-5th Gear project), 1999 Esprit V8SE ('02 rear) 1999 S350 #002 Esprit GT1 replica Link to comment Share on other sites More sharing options...
jamie c Posted November 25, 2021 Author Report Share Posted November 25, 2021 Does anyone have a way to drain down the coolant system just below the thermostat housing. Last time I had the thermostat housing off they were in place and thermostat as well. I’m scratching my head on this. Quote Link to comment Share on other sites More sharing options...
jamie c Posted November 25, 2021 Author Report Share Posted November 25, 2021 I only torqued the bolts to 15 lbs 185 inch pounds. Quote Link to comment Share on other sites More sharing options...
mike_sekinger Posted November 25, 2021 Report Share Posted November 25, 2021 You can drain the cylinder head coolant by opening the heater take-off from the back of the block (the Y-pipe in the image). 1 Quote 1996 Esprit V8, 1998 Esprit V8 GT, 1999 Esprit S350 #002 (Esprit GT1 replica project), 1996 Esprit V8 GT1 (chassis 114-001), 1992 Lotus Omega (927E), 1999 Esprit V8SE, 1999 Esprit S350 #032, 1995 Esprit S4s, 1999 Esprit V8 GT (ex-5th Gear project), 1999 Esprit V8SE ('02 rear) 1999 S350 #002 Esprit GT1 replica Link to comment Share on other sites More sharing options...
jamie c Posted November 25, 2021 Author Report Share Posted November 25, 2021 ok that’s better than draiining the system too much. How about when I want to refill. Whats the technique to refill before I start the engine. Quote Link to comment Share on other sites More sharing options...
mike_sekinger Posted November 26, 2021 Report Share Posted November 26, 2021 If you raise the heater take-off then you can refill at the header tank. You should follow the steps in the Service Notes for bleeding out the system. I`ve found that this is also easier if the back of the car is jacked-up. Quote 1996 Esprit V8, 1998 Esprit V8 GT, 1999 Esprit S350 #002 (Esprit GT1 replica project), 1996 Esprit V8 GT1 (chassis 114-001), 1992 Lotus Omega (927E), 1999 Esprit V8SE, 1999 Esprit S350 #032, 1995 Esprit S4s, 1999 Esprit V8 GT (ex-5th Gear project), 1999 Esprit V8SE ('02 rear) 1999 S350 #002 Esprit GT1 replica Link to comment Share on other sites More sharing options...
jamie c Posted November 26, 2021 Author Report Share Posted November 26, 2021 Hi Mike, when you say raise the heater take off, do you mean by lifting the back of the car up, or by adding a lenght of hose hose to the y pipe a lenght long enough to go above the motor and refill through this extension. Quote Link to comment Share on other sites More sharing options...
mike_sekinger Posted November 26, 2021 Report Share Posted November 26, 2021 The Y-pipe is attached to flexible rubber hoses off the back of the stub pipes in the rear of the block. You can lift up the pipe. If access is difficult or you cannot lift it enough then your other suggestion would work. Anything to elevate the exit of the hose while you top it up. Quote 1996 Esprit V8, 1998 Esprit V8 GT, 1999 Esprit S350 #002 (Esprit GT1 replica project), 1996 Esprit V8 GT1 (chassis 114-001), 1992 Lotus Omega (927E), 1999 Esprit V8SE, 1999 Esprit S350 #032, 1995 Esprit S4s, 1999 Esprit V8 GT (ex-5th Gear project), 1999 Esprit V8SE ('02 rear) 1999 S350 #002 Esprit GT1 replica Link to comment Share on other sites More sharing options...
jamie c Posted December 7, 2021 Author Report Share Posted December 7, 2021 ok good news I have sealed the thermostat housing by using a light coating of RTV silicone and snuging up the three fasteners and letting cure over night. Torqued in the morning and refilled the cooling system by jacking up the back of the car and refilled with coolant through the Y pipe with a hose added extra length to help refill, noticed I could of refilled through the heaader tank as I had raised the the back of the about 18” higher than the front and saw header tank filled up ad well. I started this project due to coolant loss that was very small and steady, installed a new water pump the week before. I have driven the car a total of 150 miles over the last two days and gave it plenty of occasions of lots of boost and haven’t lost any coolant. Yeah! There were times I thought I might have headgasket issues. Thanks 2 Quote Link to comment Share on other sites More sharing options...
mike_sekinger Posted December 7, 2021 Report Share Posted December 7, 2021 Well done. Good to have a positive outcome with little outlay. Enjoy yourself. Quote 1996 Esprit V8, 1998 Esprit V8 GT, 1999 Esprit S350 #002 (Esprit GT1 replica project), 1996 Esprit V8 GT1 (chassis 114-001), 1992 Lotus Omega (927E), 1999 Esprit V8SE, 1999 Esprit S350 #032, 1995 Esprit S4s, 1999 Esprit V8 GT (ex-5th Gear project), 1999 Esprit V8SE ('02 rear) 1999 S350 #002 Esprit GT1 replica Link to comment Share on other sites More sharing options...
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