My rover metro 114 sli every now and again the temp goes up and the water in the expantion tank boils and when I open the cap it ****es out and the water drains so I fill it back up and its ok for a while it could be 10 days 20 days but lately its got a lot worse and is happening much freqently mechanics have told me it is the thermostat so I replaced it with a brand new one and its still happening then they said it must be the head gasket but I dont think it is as im not loosing water and theres no white creamy stuff in the oil I think my self its the water pump or its a blockage somewhere someone please help
How about flushing the system and radiator? What kind of outside temps are you driving in? Any relation to the overheat events?
December, 24, 2010 AT 2:18 PM
You don't have to get "Creamy" stuff in the oil when a head gasket blows. At all depends on the design of your engine and where the gasket blew.
When you drive for extended periods on the highway, does the car overheat? (Above 55mph) Do you get any smoke out the tail pipe during the first few minutes of start up? These are signs of a blown head gasket.
A quick way to check: Remove the resevoir cap and rev the motor a few times to 1500 rpm. If you see large bubbles in the coolant, blown gasket. (This isn't a foolproof method)
Also, feel both upper/lower radiator hoses after it overheats. If one is too hot to touch, and the other is barely warm, blown gasket.
The reason for this is there are exhaust gasses blowing through the leak in the gasket. This causes bubbles in the cooling system that get trapped in the block, heater core and radiator. This prevents the coolant from circulating. Thus the overheat issue.
Now if you eliminate this as a cause (Suggest the above to your mechanic), then make sure the fan/fans are coming on, make sure your cooling system is holding pressure, and have the system pressure checked. Finally, make sure the system is bled of all air.
December, 24, 2010 AT 8:58 PM
My grand daughter was experiencing this same type problem with her car and it turned out she is losing a little anti freeze over time. When it finally gets low enough to not circulate completely the pot boils over, she fills system, and it's good to go for another period of time, usually about a month. She's in another city so I just tell her to keep better eye on it(refill) and it wont boil over. The leak is not apparent leaving spots on ground. I figure when it gets worse i'll know where to fix it. It's winter where we are now, so the problem is not exacerbated by the hot weather.
December, 24, 2010 AT 10:46 PM
There's only two places coolant can go, either outside on the ground, or inside the engine.
If there's any loss of fluid whatsoever, but it isn't showing up on the ground, then it's going inside the engine. Either into the crankcase (oil), or into the cylinder and out the tail pipe.
A simple pressure test will expose a leak entering the crankcase. This won't necessarily reveal a leak into the cylinder.
What happens is when the engine is under a load, the head separates slightly from the block, allowing cylinder pressure to leak through the gasket and enter the cooling system. When there's no load, the headbolts create a tight enough seal that a pressure test won't be able to overcome like the cylinder pressure.
Though there's a couple ways to detect this, the most sure fire way is with a chemical tester that detects the presence of exhaust gasses in the coolant.
My advise: Fix this before you overheat and blow the motor while you're far away from home.
December, 26, 2010 AT 2:26 PM
I would also have the radiator core cleaned, as you may have partial internally blocked core tubes, common problem with rover cars that do not have correct coolant, a back flush will not be enough, the radiator should be cleaned by a radiator shop.