Cocker Spaniel - growling

Question
Help please.  Our cocker spaniel, Benson is 11yrs old and he is very placid however when he gets in a car or goes under the bed he will stay in the car or under the bed for a minimum of 24hours without food or water eventhough we leave it for him and he growls viciously when you go near the car or the bed.  his eyes go distant and he seems vague, he froths at the mouth sometimes and shakes when he growls.  is this common in older cocker spaniels or is he just loop the loop.  help as we are thinking of putting him down just in case he bites someone.  He is golden cocker spaniel.

Answer
You don't say how long this has been happening.  I strongly advise a vet checkup and it sounds like Benson may have a little senility problem.  This can be addressed with medication.

Is he okay when not under a bed or in the car?  Has he ever bitten or even suggested he might?
Please at least give your vet a chance at helping to solve this.  Many behavioral changes are due to physical causes.