why's it over heating

There is a reason they are called "Vague-lia". I recall my 78 308GTS would occasionally require a gentle tap on some of the gauges, for them to come up. It might be worth having it sent out to an instrument specialist for a tune up/adjustment. I think is was also the water, but it would read intermittently low, and a tap would bring it up.

 

Its possible that your water pump impeller isn't far-enough 'in' the engine to move your coolant around, and is only cavitating it in-place. One of the best Indie F-car mechanics on the East coast told me 308 water pumps need to be 'tuned' to really work their best. Take a look at your water pump pully alignment with the alternator and the main pulleys to see if something's out-of-whack. I'd also check your fans, try a new coolant cap, and keep bleeding air out of the system.

 

Well, if you tapped the gauge and it's normal again...most likely the gauge. How is your oil temp? I would be more concerned if it was high as well. When do the fans kick in? Should be just about 195 when they do. I had a similar problem when I changed some hoses...the temp was higher, and still runs a tad high but mine is air related, so it appears. My oil temp is fine so I just keep an eye on things.

 

I'm good...I drive the car most every day. Problem now is I have her tuned just about right and I am worried about the old TRX tires. So I take it for short stints anyway! Great cars.

I think your problem is the gauge but it's best to have it checked out...one good overheat is all it takes you know

I scan my gauges like a pilot! Sometimes they bounce around in unisen so I know I have ground/connection issues. Just another item on my list.

Another thing you can try is sticking a thermometer in the expansion tank, see what it reads. It may be cooler than normal in the tank but if it reads way up there you know you have a problem.

 

Get an infrared temperature gun and "shoot" the temperatures at the radiator inlet/outlet.

It's the handiest tool in the box and you won't even get your hands dirty

 

Pull out the dash pod and clean the connections on the back of the gauge. This resolved my problem with slightly higher than normal readings. Unfortunately this was my last step after already replacing the sender, cap, 2 pole radiator unit, bleeding the air, thermostat and verifying operating temps with an infrared unit. I was about to purchase a new gauge but decided to clean the connections first as a last ditch effort. Mike remember we live where it is has been 100+ for the past few days. this shouldn't effect the operating range as the fans should kick on but it certainly doesn't help keeping the temps down especially in traffic. Good luck.

Dan

 

Be sure to move the heater levers to hot, when bleeding the air out of the system. (air gets trapped in the heater core)

 

IR thermometers are very inexpensive online...check Ebay. I bought mine from a fellow F-chatter that sold them for something like $25 or so, several years ago.

 

Mike,

After replacing all the cooling components and still getting higher than normal readings I called Ben at Salerno Motorsports and explained my problem. he told me to bring it over and leave it running in the parking lot, come get him and he would verify temps with the infrared gun. My temps via the gun were normal but the gauge was reading high. That is when I decided to look at a new gauge but decided to clean the connectors first. That solved my problem and it was free.

When Eurosundays are going on in Sacramento (pavillions) I am usually playing golf. Sunday is my alloted day for myself. I do need to hang up the clubs some weekend and stop by the event. Yes my car is back up and running after the fuel line replacement and no fires to date. I must have done it right.

I agree with getting parts from Doug. I inquired about a used bellow from the air intake to the air filter box as mine has a small rip. He was very honest and said the ones he had in stock he wouldn't put on a car of his.

Try cleaning the connections at the back of the gauge and see if that helps. I'll bet it does and again it is free.

Hopefully I'll see you soon at a local event.

Dan

 

My 308 overheated one minute and was fine the next.
It turned out to be a loose connection on the fans. I didn't clue in until someone noticed they weren't turning.
Ended up having to replace the water pump after that.
Brent.