How long does it take to repair a head gasket?
You don’t repair a head gasket, you replace it.Once I had a rally car - a bit of a ratty old junker if the truth be told - that had a 2.3 litre overhead cam engine. It was a bit like this, only this one is way nicer:Anyway I was heading off to do a rally on some Friday night. On the Thursday, the day before, I took it out for a blast around the lanes to shake down any last-minute faults, and blew the head gasket. It was too late to do anything about it that night, so next morning, I got up at the crack of dawn, stripped the engine down to the point of having the head off (it was OHC, so that involved also removing the cambox, timing belts, etc. plus the exhaust manifold, inlet manifold and carburettors) By then it was almost 9am, so I drove to the nearest big town - 25 miles away - to get a replacement head gasket set. 25 miles back, and by 10am had the head all cleaned and ready to be reassembled. Engine back together and running by 12pm, I then had to drive it 250 miles to where the rally started. It all went smoothly and I made it with plenty of time to spare.So the answer to your question, for me, on that occasion, for this car, was about 6 hours, including an hour to fetch the parts. Sometimes what you need, apart from the basic skills, which in my case don’t amount to all that much, is a great big incentive!As I recall, the rally ended in disaster, but that’s another story.
Can a clogged catalytic converter unclog itself?
Well, it can happen that they will de-clog on their own, but usually need a helping hand. If it is utterly blocked, then dismantling and manually cleaning is the only solution.If the ceramic material inside is melted, then change it.Most modern Cats are stuffed with a ceramic honeycomb structure, unlike the older ones that had complex filters with platinum wool amongst other stuff inside them.One of the reasons they get clogged is people lugging around in fifth gear making lots of soot which clogs the honeycomb.A faulty EGR valve (gas recirculation) will do the trick as well.Faulty injection, allowing to much fuel to come through the exhaust can cause the honeycomb to melt when it starts burning the fuel... (replacement)But you can clear a blocked (not 100% blocked) converter by getting it hot enough to make it finish what it is supposed to do.The garages here in France have a naughty technique, they hoist the car up on lift with the motor going flat out, and stand underneath it holding a fire extuinguisher, just in case it sets fire to the car, or any flames from the now burning soot comes blasting out of the rear.It is a dangerous technique in my opinion, and not good for the engine, but it works. I don't suppose it works everytime either.So if you have a CAT that is partially blocked because you mooch around in fifth gear or have bad driving habits, you could try driving the vehicle hard enough to heat the CAT as it should be, where usually it can clear itself.So , if it is soot build up, there is hope for you, to unclog it without taking it off the vehicle and or changing it, if it is hard blocked with mineral deposits, unlikely. If it is melted, its got to be changed.
Is it okay to drive your car without thermostats?
If you take out the thermostat then the coolant will just flow 100% by the water pump. Assuming that your system is properly sized so that cutting off flow with the thermostat will result in the proper operating temperature being met then running without a thermostat will always result in a lower than intended operating temperature.Here are some things that will happen:Your engine will run cooler than the desired temperature most all of the time andit will pollute more since it is tuned to run at the designed temperatureYour heater will take longer to become effective since the coolant is used to warm the heater core heat exchanger so you may, on cold days take longer to warm the cabin andmore importantly, it will take much longer to defrost the windshield using the defroster function.Probably it won’t hurt short term to the car engine itself, I don’t think. But in the long term operating it significantly below the designed temperature could have a number of effects, perhaps on lube viscosity, various carbon buildups that lead to other engine performance problems and possibly permanent damage.I once had a mechanic shop replace the thermostat and flush the coolant. When I get it back the car took forever to warm up the heater and get the engine to the temperature. I eventually took off the thermostat housing and found he had placed it about half way off and clamped it down with the housing out of position- it didn’t leak but the gap on one side pretty much made it free flowing.
What is wrong when the coolant tank starts bubbling after driving your vehicle for a while?
I assume you mean that the coolant is boiling up into and out of the overflow bottle.(picture is of a fancy stainless steel bottle … I have never owned a car with anything other than a plastic one, but they look pretty much like that … and who knew finding a decent photo would be so difficult)So why is your coolant boiling over? Could be:Cooling fan is not running - because:motor brokerelay brokefuse is brokebelt is slipping (if you happen to have a mechanical fan instead of an eletrical one)Water pump is not working - because:motor brokerelay brokefuse is broke (if you happen to have an electrical water pump).belt is slippingRadiator is gacked / corroded and no longer flowingInsufficient coolant - so you don’t have enough material to exchange enough heat … and what you do have is getting boiled … so where did the coolant go? You have a leak somewhere?water pumpradiatorhoseoverflow bottleBad coolant mix (either way too much anti-freeze or none) - this seems unlikely as a sudden onset thing (the chemistry in your cooling system doesn’t just change overnight and many cars will run plenty cool on just water).Cracked head gasket - although you should see coolant / water in the oil and probably be getting smoke out out of the tailpipe (you can usually smell it too) - depends on how bad the crack is I supposeThermostat is broken - this is the thermostat that is inside the engine, and used to either pass collant through the engine block or shunt it from the block (this doesn’t usually present as a boil-over but it could - and it is usually cheap to check and relatively easy fix).All of these things can cause a coolant over-temp … and hence the boil-over into the overflow bottle.