MGF overheating, head gasket already repaired, help?

Probably is the head gasket again.

These things usually fail repeatedly, and once these fragile engines have overheated once, they're scrap.

Things that can cause an increment on temp in an engine with a new gasket, showing on the increment of temp on the oil - in my judgement (15 of hair dresser) are:

1. Engine's coolant Temp thermistor (actually called 'element), located onto the mid-section between the heads. These things are 'linear' meaning that an increment in resistance of (example) 10 Ohms, will mean a change in Temp equivalent to xyz degrees. I would pull it out and tested - in hot water at 195 F to read the Ohms it's supposed to read (consult with Google; in my Pontiac Trans Sport it should read something like 300 Ohms). This tells the EMC (electronic module control) to switch on the radiator fan motor.

2. Try using a lower Temp Thermostat; I have installed a 160 F Thermostat in mine, so when Temp reaches 160 F it opens and cold coolant flows in.

3. Check for Oil PRESSURE, If the pressure is low, there is heat build up.

4. If EGR is stuck open, gases recirculating from the exhaust WILL increment the engine's operating temp.

5. Back flow pressure coming from the exhaust is too high, meaning the exhaust ratio is hampered by "something" not allowing rapid flow of gases OUT of the engine, incrementing its operating temp. I would check condition of catalytic converter. Flow out of the exhaust pipe, etc. Is it restricted for some "enhancement"? One of those 'bullet" pipes? They sound good... that's all they do.

6. How about "timing"? If the engine is advanced all the time, then there is shown in the incremented temp. Not more than 7 - 10 degrees by rule. Check it out with a Manual (not Manuel, btw, in case you are in Mexico).

7. Exhaust valves MUST have an exact clearance; if this clearance is LESS, gases exiting the cylinder head WILL heat up the valve's stem, and - while they are not YET burned - WILL produce an increment in temp. They MUST have the clearance required by the manufacturer. I have burned a couple of heads to know that the mechanic "adjusted" them by ear! Specially if they have roller lifters or a system that makes them more delicate to adjust.

8. Forgot to mention that -if they goofed on the head's gaskets, they may have installed the WRONG one there, which might have had wrong oil holes and lubrication might be hampered; check its flow and pressure if possible.

So if what you said "mfg" does not mean "My Girl Friend" but a real engine and a mechanical problem at that, take your pick. Hope it helped.

Get a test done on the coolant for combustion gases. It is a simple colour change test the garage should be able to do.

If it has combustion gases in the coolant then the head is cracked or they made a mess of doing the head gasket.

Is the timing right.

Thermostat stuck.

Air lock?

I am not convinced that there is not still a leak from the head.

When most garages repair a head gasket they never carry out a backflush, to do this you reverse the flow of water so instead of the water /coolant flowing from the top of the engine in to the rad and then back in to the engine you reverse the flow and you would be amazed at the amount of debris that will come out try that with the rad and the full cooling system

Why would you even make a decision to get a fish when you aren't getting the correct tools to care for one? Any who, you ought to have dechlorinator/ water conditioner. Chlorine is one factor to fear about in faucet water, however heavy metals and chloramines don't evaporate which means that that your fish are most likely suffering right now. Go to the pet store at present and get both Stress Coat Plus or prime, however if you cannot in finding those, any dechlorinator will work. Simply get it today or your fish will not final very lengthy.

Mgf Thermostat

Check the flow through the radiator because it may be a bit clogged, especially if you had problems with the head gasket earlier. Sometimes a good flushing or replacement is needed.

If it is an aluminum head, it might have taken damage from overheating when your head gasket failed.

A thermostat uses a bleeder hole../

Look at the thermostat " flange "

If there is no bleeder hole--the engine can over-heat for a short time..

..and also make the thermostat act in a jerky kind of way..

Use a very tiny drill bit..

Like the size of thin spaghetti..

Drill a small hole--to allow coolant to bleed past the thermostat.

Nope