How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site. Ask follow up questions if you need to.
  • Go back-and-forth until satisfied
    Rate the answer you receive.
Ask Robert Your Own Question
Robert, UK Qualified Car Technician
Category: Car
Satisfied Customers: 5214
Experience:  Fully qualified / self employed garage technician in the UK
Type Your Car Question Here...
Robert is online now

The cabin is taking to long to warm up then when I hit a

This answer was rated:

The cabin is taking to long to warm up then when I hit a motorway it cools back down. No leaks. Changed the waterpump that's ok and thermostat
Assistant: Has the vehicle ever overheated? And when was it last serviced?
Customer: Serviced 4 months ago not overheated however did have a short spike in engine temp once
Assistant: What is the make/model/year of your car?
Customer: Hyundai i40 premium
Assistant: What year is your Hyundai?
Customer: 2014
Assistant: Are you fixing your vehicle yourself? What have you tried so far?
Customer: Flush, twice, thermostat genuine part new. New waterpump
Assistant: Anything else you want the mechanic to know before I connect you?
Customer: No


Do you know if both coolant hoses to matrix into the bulkhead are both hot/warm?

What about radiator are both hoses warm?

What does the engine temp sit at when running or does it fluctuate?

Customer: replied 8 months ago.
All hoses warm
Customer: replied 8 months ago.
Engine temp fine except 1 short spike 2 weeks ago
Customer: replied 8 months ago.
I'm not calling

Ok... could be air lock in the system maybe are you sure your hot/cold blend doors are working?

Customer: replied 8 months ago.
Never heard of them the heat is going up when engine warms but going down if I go fast I.e more airflow and I can adjust once warm so yes seem to b working
Customer: replied 8 months ago.
We have done to waterflushes bottom up and top down
Customer: replied 8 months ago.
Two waterflushes

Normally the engine running cold like that you'd think it was stuck open thermostat..given that its been replaced aswell as the asumption could be that you have air trapped or an air lock somewhere in the system.. you need to ensure the heater is set to hot setting..ideally if you know someone with a vacuum bleeding kit "you need access to compressed air" - try bleeding the system that way and see if that helps..

Customer: replied 8 months ago.
We havnt tried a vacuum bleed could there be air still even though we flushed twice and re filled

Well flushing doesnt get rid of air pockets..If you havent bled it might have air trapped in the matrix or somewhere in the system.the spike in temp suddenly could be a maybe try the vacuum method and see if that helps.unless your sender on the thermostat housing you have access to infrared thermometer? might be worth once the engines hot go around the system and see if their is any temp differances anywhere ie: cold spots that could be clue to an internal blockage of sorts and whether or not the temp gauge the cars sensing is correct or not..

Robert and other Car Specialists are ready to help you
Customer: replied 8 months ago.
Ok thanks