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Super Mechanic
Super Mechanic, Master technician
Category: Chevy
Satisfied Customers: 16825
Experience:  29 yrs. exp., ASE master, cert. in G.M. electrical, a/c, susspension, brakes, electronic steering
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Temlerature guage fluctuates when driving but not when

Customer Question

Temlerature guage fluctuates when driving but not when idling. Trying to bleed air and it just blows air all day long. New water pump and thermostat and new intake gaskets. 05 Chevy Venture
JA: How many miles are on the car? What size is the engine?
Customer: 200K something and v6 ? I dont have it here to see. My mechanic has it and is scratching his head at this point.
JA: What is the model/year of your Chevy?
Customer: 2005 chevy venture
JA: Are you hoping to fix this yourself? What have you tried so far?
Customer: No. Mechanic has ir but cant figure it out. Just want my van back so im searching. New thermostat and water pump and new intake gaskets. Replaced radiator and gaskets last april. Same mechanic. No coolant leaks but cant get air out.
JA: Anything else you think the mechanic should know?
Customer: No
JA: OK. Got it. I'm sending you to a secure page on JustAnswer so you can place the $5 fully-refundable deposit now. While you're filling out that form, I'll tell the Chevy Mechanic about your situation and then connect you two.
Submitted: 3 months ago.
Category: Chevy
Expert:  Super Mechanic replied 3 months ago.

Hello and welcome. My name is ***** ***** I will be happy to assist you today.


It sounds like the engine is producing the air. Possibly from a head gasket pumping exhaust gases into the cooling system.

The first thing that you want to do is check the cooling system for any exhaust gases. Make sure that it’s full first. There is a tester for that, that you can get from Autozone for about $20. They will normally lend you the tester and you just buy the fluid for about $8. It comes with instructions, but there is a blue fluid that is used in it, if the fluid turns yellow, that is exhaust gases.


Block tester available is:

Napa BK.(###) ###-####/p>


Part Number:


*****You will want to check it at different RPM’s and at different temperatures***



If there are any exhaust gases in the cooling system, that will cause more pressure than desired and will allow the engine to burn coolant and/or heat the coolant up too high. Most times not filling the crankcase with coolant either and not smoke out the exhaust.

If there are, then there would be an internal engine problem, like a head gasket or head.


Please don’t forget to rate the answer, **** THAT IS THE ONLY WAY I GET PAID **** if you need any more on it, I will be here.


Customer: replied 3 months ago.
It is at a mechanic shop. It is not a clogged heater core or anything like that it was tested and definately a pressure issue. Water pump and thermostat were replaced. Intake and head gaskets were replaced. Found it had come apart in two places from replacing it just last year. Now that its all back together same problem. Said he cant get the air out. Idles just fine. Will idle over 30 min but when you start to drive temp slowly goes up then flucuates