That was the first sign of wennys engine going bang big style in the monte dicko we were out in it the wed night and there was a bit of mist coming on the screen through the passenger side vent, sunday night we were out in it it melted 2 pistons and cracked the block but you would know that as you wernt far behind us , ide take the head off as a precaution if i was you mate if you do put the t4 on and there is a problem it could make things alot worse..