Temp up and down after coolant flush

flushed the coolant out of my 455 today . During the test drive it stayed mostly at 195 ish but while just cruising at 55mph will go up to 250 for a few seconds then back to 195 . Any idea what could do this? Thermostat is a 180 . Thanks

 

I tested it first on the stove and it opened but don’t know how hot it got . First time I went for a drive it was at 180 for a while then to 195 but still went to 250 for a few seconds . Should I just try another one ? The original one I swapped out stayed at 210 mostly and that jumped high also . .

 

Air in the system. search. ( hole in thermostat )

 

like this one ?

 

ya. just put the hole at 12oclock.

it can take 4ever sometimes to burp the air out.

 

Thanks I’ll try that . I’d heard of people doing that and seen some stats with them in all ready

 

Once the stat is back in hole drilled just run the engine with radiator cap off as normal to get the air out yea ?

 

Yes.

 

Here's how I do it, and I myself never have an issue with air pockets with an exception or two, I do Collision work so you can imagine ive got quite a few radiator replacements under my belt,...ha,..but the trick is simple fill the rad and let it sit until the coolant settles and stops then run the car with cap off until the stat opens the level will drop then finish filling it

 

Thanks mate

 

I've always put the vent hole in, another trick I learned as a lad was to jam it open with a wine gum (lolly) to get flow going instantly on difficult to burp motors, just melts away with heat then works normally

 

Well I have some good tips here guys . I’ll let y’all know how it goes later , cheers Simon

 

I had to look up wine gum. basically a gummy bear here in the states. Sweet I like.

 

Haha I already knew what a lolly was but haven’t heard it since I moved to the states .
Got the stat back in with a hole drilled in it . Waiting for it to drain completely then top up and we’ll see

 

Been like this for 10 minutes

 

Getting better