Hello and welcome to JustAnswer!
I'm not sure exactly what type of test you did to check for exhaust gases in the cooling system, but the best way is with a Block Test kit. This kit uses a vial placed over the radiator cap opening and you pour in a blue liquid and then run the engine. If there are combustion gases in the cooling system then the blue liquid will start to turn yellow.
If you're losing coolant then it either has to be burning inside the engine or leaking externally. If there are no leaks external then it has to be going inside the engine. If that's the case then that could be the reason for the radiator failures also. If the cooling system is over pressurizing or it is overheating then it can be causing the radiator issues.
Another thing that can be done is apply air to each cylinder with the engine cold and radiator cap off and see if bubbles appear in the coolant. If bubbles appear then you know for sure that you have a head, headgasket or block issue.
Sorry if my questions seem a little odd - this actually relates to a dispute between a customer and a dealer, and what I'm trying to do is get an independent opinion without biasing you one way or the other. The engine issue itself has since been resolved - I'm trying to establish what kind of tests would be needed to detect the problem
The first overheating and radiator replacement occurred a couple of years (and a few thousand miles) prior to the customer buying the vehicle. The dealer did not inform the customer of this prior to purchase.
The tests the dealer did after the 2nd overheating & radiator rupture were these:
They concluded from this that the problem was an air-lock in the system, and said the van was performing as normal.
A short time after this there was another overheating incident, and a different garage confirmed the head gasket had failed, with a "bubble test". They stripped the engine and found the actual failure was caused by the cylinder head leaking through No3 exhaust port, which ultimately caused long-term damage to the head and gasket .
The crucial question is, could the original leak have gone undetected by those two tests the dealer carried out? They are claiming that all the damage occurred after they returned the van to the customer, and their argument is that the negative tests prove this, although it should be noted there's no documentary proof of the tests themselves.
I'd like to know if you agree with their position, or if you feel they could have gone further in diagnosing the problem
I'd also like your opinion as to whether this sounds like a sudden, short term problem, or something that would have built up gradually over time.
Okay so just to clarify what you mean by "50/50", are you saying you believe that one of those two outcomes definitely did occur? ie either:
1) The leak was there long-term, but was not detected by the tests the dealer carried out (for whatever reason), resulting in the eventual head damage
2) The head damage occurred at the original overheating, implying presumably that the dealer deliberately turned a blind eye to what must have been obvious damage
Please correct me if that's not the correct interpretation. Thanks again.
I'm now in the process of preparing my case against the dealer regarding this engine issue, and I'm hoping to submit your advice as an expert witness statement. Would you be willing to complete a short statement and send it to me? I will pre-prepare a template in the correct format, so hopefully it'll be a simple case of pasting in your comments, signing and dating the form and posting it to me. Of course, I'll happily add a bonus to your account to cover your costs and time!
If you're happy to do this, could you first reply to this message with your name, background and short summary of qualifications? I will need to submit these details to the court to ask permission to use your statement.
I'll help any way that I can but please remember the site's terms of service dictate that correspondence is for informational purposes only and cannot be considered legal advice.
Due to site terms of service and personal security reasons I won't be able to give any personal contact information.