Inside car not getting very warm so bought a 88c thermostat,took the housing of to change it and found no stat at all so put my new 88c one in all was fine on a short run.come to work in it this morning got warm in the cab but my motor started running like a bag of knackers coughing and farting, it has to be down to the stat but why,feel sure if I take it out as it was it will run fine but surely can't be good with no stat in