I'm not sure what you mean by "serious car." Sophisticated? Powerful? Expensive?
Perhaps what you want to say is "serious-looking car," that is, a car that looks conventional or traditional.
The adjective "serious" does not collocate with the noun "car":
Oxford Collocations Dictionary for Students of English, 2nd edition
Serious is used with these nouns: accident,accusation,actor, actress,ailment,allegation,allergy,alternative,analysis,answer,artist,assault,attack,attempt,attention,attitude,bid,blow,blunder,bout,boyfriend,breach,breakdown,burn,business,case,casualty,challenge,challenger,charge,clash,collector,collision,commitment,competition,competitor,complaint,complication,concern,concussion,condition,conflict,confrontation,congestion,consequence,consideration,contamination,contemplation,contender,conversation,corruption,crack,crash,crime,criminal,crisis,criticism,damage,danger,debate,debt,decline,defeat,defect,deficiency,deficit,delay,dent,depression,deterioration,dialogue,difference,difficulty,dilemma,disability,disadvantage,disagreement,disappointment,discrepancy,discussion,disease,disorder,dispute,disruption,dissent,distortion,disturbance,doubt,downturn,drain,drawback,effect,effort,embarrassment,emergency,engagement,enquiry,erosion,error,escalation,expression,face,failing,failure,fashion,fault,felony,fiction,fighting,fire,flaw,foul play,fraud,gap,girlfriend,handicap,harm,hazard,heart attack,hindrance,historian,illness,imbalance,impact,impediment,implication,incident,inconsistency,inconvenience,indigestion,indiscretion,infection,infringement,injury,interest,irregularity,issue,lack,lapse,leak,limitation,look,loss,matter,menace,message,miscalculation,misconduct,misgivings,mishap,mistake,misunderstanding,misuse,mood,move,music,musician,need,neglect,negotiation,note,objection,obstacle,offence,omission,opposition,outbreak,overtone,peril,pest,possibility,prejudice,problem,quarrel,question,reading,recession,reflection,relationship,repercussion,reservation,resistance,responsibility,rethink,reverse,revolt,rift,riot,risk,rival,row,scientist,scrutiny,setback,shopper,shopping,shortage,shortcoming,side effect,situation,split,strait,stroke,study,subject,symptom,talk,test,thinker,thinking,thought,threat,tone,training,trouble,underestimate,undertaking,unrest,violation,violence,voice,weakness,worry,wound,writer
When you block a person, they can no longer invite you to a private message or post to your profile wall. Replies and comments they make will be collapsed/hidden by default. Finally, you'll never receive email notifications about content they create or likes they designate for your content.
Note: if you proceed, you will no longer be following .