Coolant Overflowing / "low Coolant"

Hey guys

Replaced the water pump and thermostat about a month ago as water pump was failing and leaking out of weep hole. I have put a few hundred miles on the car. All of a sudden the temp gauge rises pretty high on a cool early morning ride to work. The more RPM and fan action would help keep it cool. Got to work added some coolant to the overflow as I opened radiator cap (after cool) and radiator was full. Added to the overflow tank drive it the coolant light comes out and when I get home you can see where th overflow bottle is full and has been dumping out the overflow hole.

Why would it be pushing coolant out the overflow but showing low coolant; could it be a stuck thermostat?
The coolant light will come on prob 2-3 minutes after reaching normal on the temp gauge.

Any suggestions would be appreciated.

mikestang63 said:

what does your gauge say?
if you are overheating in traffic or at idle. it is either a water pump, fan, thermostat, clogged radiator or loose belt. if overheating at highway speed, it is airlfow problem, air damn missing on the bottom of the car, seal on the firewall to hood damaged or missing, or clogged radiator

Other things to check

• bad radiator cap
• leak in radiator, hoses overflow tank
• air in the system

Do you have underdrive pulleys by chance?

Click to expand...

Hi mike

The car will warm up to mid range temperature around the M in normal.- seems the lower the rpm the higher it will get. It creeps up to the R. If I'm stuck behind traffic in 4th gear it will raise the temp: if I DS into 3rd gear and bring the RPms over 2100 it seems to cool off and go back down.

I drive it about 25 minutes to work and kept an eye on it each way today and if RPms were up it was ok.

I just took it out to warm it up and go down the road; when I got home it was hot and I felt the top and bottom hoses and they were not firm I could squeeze them a little bit. When I squeezed it I could hear a clicking noise in the radiator cap. The overflow tank seems to fill up and spill over sometimes, other than that there is no fluid leaking.

Bad radiator cap? It didn't seem like it was fully pressurized?

Or air in the system - what is the easiest way to bleed the air out of the cooling system?

I am not sure about under drive pulleys - how could I tell and what effect?

I put a new water pump and new thermostat in it about 2 months ago or about 300 miles. Didn't have any issues until about a week or two ago. I don't drive the car very often

Any help would be appreciated - my truck is in the shop hoping I can drive it in to work again tomorrow.

TY

John

skyline247 said:

I have an '88 and my low coolant light comes on and off even though my coolant levels and engine temp are fine. I have read that it's possible the low coolant sensor has gone bad and needs to be cleaned or replaced. I haven't cleaned mine yet so I don't know if that will fix it yet. I'm not sure if it's the same problem you have but I figured I'd mention what I've found. I don't know about your temp spiking though.

Sent from my Nexus 6 using Tapatalk

Click to expand...

The low coolant light comes on and off - it's weird it seems like late night and early morning when it's cold it comes on but during go day the low coolant sensor never comes on. I ordered a new one today

mikestang63 said:

what does your gauge say?
if you are overheating in traffic or at idle. it is either a water pump, fan, thermostat, clogged radiator or loose belt. if overheating at highway speed, it is airlfow problem, air damn missing on the bottom of the car, seal on the firewall to hood damaged or missing, or clogged radiator

Other things to check

• bad radiator cap
• leak in radiator, hoses overflow tank
• air in the system

Do you have underdrive pulleys by chance?

Click to expand...

So I changed out the cap today: I didn't drive it to work today. I bleed the system than out a new cap on. While bleeding the system neither the top or bottom hose pressurized. I saw a few bubbles but not much. I'm assuming bad thermostat? Just replaced it a few months ago but didn't seem to me like it opened.

Any thoughts would be awesome