It`s been six weeks 
I agree that he should get the engine cleaned, completely. Wash it until nothing is left on it, no dirt, no oil, nothing; get the entire engine compartment fully cleaned up.
It is very very very cheap and easy to do that and in comparison to newer cars it is also much safer with less complications. And plenty of space.
And posting good quality pictures would be tons of help, too; or uploading a youtube video (or more) for the forumers to see.