Browse over 9,000 car reviews

    guides

    adventureguide

    evguide

    familyguide

    tradieguide

    urbanguide

    0 Logout

    Browse over 9,000 car reviews

    Corolla burnt vavles

    Toyota Toyota Advice Toyota Corolla Toyota Corolla Advice Toyota Corolla 2002
    We have just had to have the head on our 2002 Corolla, which we converted to gas in 2008, rebuilt due to burnt valves. The seats have been replaced, but we have been informed that it is inadvisable to use gas, as the problem is likely to re-occur. We have discovered that the gas can be augmented with a drip-feed additive lubricant which may "cool" the combustion. Manufacturers of the "drip-feed" lubricants produce sales brochures with generalised comments extolling the protective properties of their product, but no empiric facts to substantiate the products' use. Further enquiries have unearthed another apparently strange approach, which is to run the vehicle on petrol for a quarter tank for every full tank of gas. The use of petrol over, say, a run of 100 km and then gas for, say, 400 km to create a long-term beneficial residual influence from the petrol, does not appear to be logical. It is suspected this approach has been more to ensure that petrol does not go stale in the tank. It has also been suggested that the engine management system should be checked regularly to ensure that petrol and more importantly, the gas mixture, is not too lean. What is correct?
    Answered by CarsGuide
    23 February 2012
    Graham Smith

    The person repairing your cylinder head should have used LPG -  compatible valves and valve seats; had they done so you would not have any further trouble. We have been asked about the upper cylinder lubricants you refer to many times, but we have never been able to establish their worth beyond the claims made in the brochures etc. Running on petrol will only be effective on valve train degradation whilst running on petrol; periodic petrol operation is to recommended to protect the petrol system components, keep the fuel volatile, etc . Keeping the LPG system in tune should be in line with the manufacturer's recommendation for periodic scheduled maintenance and should be provided in the operators manual for the gas system. The petrol system should also be serviced in accordance with the manufacturer's recommendations. As a precaution, have the valve clearances checked every 10,000 km.

    Disclaimer: You acknowledge and agree that all answers are provided as a general guide only and should not be relied upon as bespoke advice. Carsguide is not liable for the accuracy of any information provided in the answers.
    Other Toyota Corolla Problems
    SELL ALL TOYOTA COROLLA PROBLEMS
    Related cars for sale on CarsGuide
    See more Toyota Corollas for sale

    Comments

    Have a new question for the CarsGuide team?
    More than 9,000 questions asked and answered.
    Ask now
    Complete guide to Toyota Corolla 2002
    Complete guide to Toyota Corolla 2002 CarsGuide Logo
    Reviews, price, specs and more