99 GTV6 3.0L Overheating! Mechanics stumped!
I am writing in an attempt to find see if anyone has had a similar overheating problem as I have had in the last month. This issue has certified Alfa mechanics stumped!!!!
Getting straight into it...
The car started to overhead for now apparent reason about a month ago. As it warms up, the temperature passes the regular 90 degree point and sits at around 110 (3/4 of the way up on the dial)... Mind you, this happens almost instantly and it barely sits at 90. At this temperature, the car pretty much overflows its water in about 15 min and is basically undrivable for more than ten.
This week i bit the bullet and finally took it down to a certified Alfa dealer. The initial thought they had was the radiator... they supposably did a radiator pressure test and they said it leaked at 8psi. After installing it, they quickly realised that it wasn’t the problem. So they advised me that the only logical thing was the water pump... I agreed and told them to take a look at it even though I had changed it only 1 year earlier.
Now this morning I was greeted with a phone call telling me that the problem was not the water pump... it seems that the engine doesn't have enough "flow" back to the radiator... The water pump was still in good nick apart from a small scalding mark which must have occurred when the car overheated badly the first time this happened. They also ran a test to see if any combustion gasses were going into the cooling system but both tests found no evidence of this… the car drives and sounds normal.
In the afternoon I went to the shop and discussed my next options with the mechanic. He believes that there is something inhibiting the flow of water back to the radiator. And that if the thermostat is operating correctly (according to him it is), then the next step bar removing the heads… would be to remove the entire thermostat housing block. This is the central chamber that runs along the ‘V’ of the block… The water pump feeds the chamber with the water, and then depending on the temperature of the car, the thermostat distributes the water accordingly. I told the mechanic that this was my last option and that removing the heads is something that I cannot afford right now.
Nor do I really believe that the heads are blocked / cracked. If this was the case, water would either be coming out of the exhaust, or it would be in the oil, or there would be combustion in the radiator. And since all 3 are not happening, this leaves only the possibility of a blockage in the system, which has a probability of about 1,000,000:1. I’ve heard of people mixing coolants and having it turn to a hard sludge which in turn damaged the engine, but considering the water has never been murky. This would be pretty rare. And as far as a loose piece of something having blocked a major passage point, the only major passage point is the component that the mechanic will remove on Monday, so I guess I will find out then. I am very confident that they will not find anything here either.
One thing that the mechanic did mention was that he found one of the inlet water pipes (the one that feeds back into the secondary water reserve) was not returning any water... on very little.
I guess I am writing here to see if anyone has any idea what the hell happening… Could the inlet system have something to do with it? Maybe a small blockage in there could be telling the computer that the car is cold when in actual fact it is hot? I mean… I am certain that there is a general water flow issue… I tested this by having the car fully topped up with water, and taking it on the freeway straight away… even with all that air going through the radiator… the car still overheated straight away! And once it overheats, then it starts losing water… ARRRGH! Taking off the heads to me seems like another expensive exercise that will end up not returning a solution. I have so far spent $2400 and the car is in the same condition as it was when it went in…
So in a nutshell the symptoms are:
• Car heats to 110 degrees instantly.
• Continues to lose water at this temperature (because it has reached boiling point).
• Thermostat, water pump, and cooling fans are in check.
• Temperature sensors are all responsive (this is an early model 99 and has two sensors. One at the base of the radiator and the other at the thermostat).
• The water flow back to the radiator is supposedly inhibited or reduced.
If anyone has had this issue, or may know of some other tests to run, I would be greatfull for your input.