2.8L V6 Overheating (Page 1/2)
jaredaltizer JUN 26, 03:18 PM
So, i’ve posted a previous thread on this same problem but I not have some updates and need confirmation on what might be my problem. My 2.8 V6 at idle will hit all the way up to 220. The fan comes on, I go out for a drive, the temp will shoot up to above max temp on the stock gauge. Coolant will bubble and flow out of my overflow reservoir. I have burped the system multiple times. Yesterday, I completely flushed all lines and hoses, and the radiator. When I flushed everything, tons and tons of dirt and dirty coolant water came out of the pipes and radiator. I filled the car back up with 50/50, yet I still overheat. When the car is running, I can see the coolant moving around in the t-stat housing, so I know my water pump is working. I turn the heater on in the car and it blows hot air like it should.
So logically, all of this leads me to believe that my radiator is trashed and I need a new one.

Has anyone seen these issues before? and does anyone agree that my radiator is the cause?

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'85 Fiero GT [4-speed]
‘86 4cyl (Parts Car) [5-speed]
'95 Mitsubishi 3000GT VR4 [6-speed]

tshark JUN 26, 03:27 PM
Well. There could be blockage in the coolant tubes along the sides of the Fiero, or air pockets in the system.
jaredaltizer JUN 26, 03:33 PM

quote
Originally posted by tshark:

Well. There could be blockage in the coolant tubes along the sides of the Fiero, or air pockets in the system.



I don’t really think it could be a blockage in the tubes and hoses. I flushed each tube/hose individually by disconnecting them from the rest of the system and running a hose through them until all the water coming out the other side came out clean. And I’m also unsure if it is an air pocket because i burped the system many times, squeezed hoses by hand to dislodge stuck air bubbles, but alas, that didn’t help.
olejoedad JUN 26, 04:53 PM
With the cap off of the t-stat housing, the t-stat removed and the engine running, the water should do more than 'move around'.

[This message has been edited by olejoedad (edited 06-26-2019).]

jaredaltizer JUN 26, 05:32 PM

quote
Originally posted by olejoedad:

With the cap off of the t-stat housing, the t-stat removed and the engine running, the water should do more than 'move around'.




When I said the coolant “moves around”, i mean I see it bubble and circulate. Once the engine gets up to temp, it will creep up the housing and eventually start splashing out.
donuteater306 JUN 29, 12:16 PM
That's frustrating. With all of the work you've done, this thing should be running at a normal temp. It's possible that the rust/crud you flushed our of the system had already partially plugged the radiator. Couple of things to check:

Is the thermostat actually opening all the way?

Are the transfer tubes crushed (from somebody lifting the car not knowing the tubes exist).

Does it have the correct style water pump? (impossible to tell unless you remove it and inspect the impeller)

Maybe you've already checked these things, I don't remember your previous post.
donuteater306 JUN 29, 12:23 PM

quote
Originally posted by jaredaltizer:


When I said the coolant “moves around”, i mean I see it bubble and circulate. Once the engine gets up to temp, it will creep up the housing and eventually start splashing out.



Wait a sec., someone correct me...I don't remember the coolant overflowing out of my t-stat housing when running with the cap off, no thermostat.
steve308 JUN 29, 04:58 PM
How many miles on the car? When if ever was the water pump replaced? If as you said rust and debris came out when the system was flushed there is a good chance that the impeller on the water pump has disintegrated to the point of not being able to move enough coolant thru the system. The impeller could also be slipping due to wear. Always use a water pump with a metal impeller.

[This message has been edited by steve308 (edited 06-29-2019).]

viperine JUN 29, 04:59 PM

quote
Originally posted by donuteater306:


Wait a sec., someone correct me...I don't remember the coolant overflowing out of my t-stat housing when running with the cap off, no thermostat.



A cold car, you can safely do this, from my experience. A hot car, you will get splashed and burned.

With the car running at operating temp, feel both hoses at the radiator. Both should be warm/hot. Hot on one side and cool on the other, you may have a blockage.

Try driving the car without a thermostat a while (with caps on) to see if the problem goes away.

Keep your fluid overflow reservoir full to reclaim any loss from boiling over.

Air bubbles in the system will burp themselves if the reservoir can supply the volume missing from the system. You should still try burping from the procedures found on the forum, but a functional and filled reservoir is important.

Check your HVAC to see if it blows hot air when you're experiencing cooling issues. The heater core often goes empty intermittently and will not allow your vents to blow hot air. This is a dead-to-rights sign that you are low on coolant.

The thermostat being out will likely leave the car in mostly open loop so expect your cold fast idle to remain longer than normal when running without a thermostat.
jaredaltizer JUN 29, 05:21 PM

quote
Originally posted by steve308:

How many miles on the car? When if ever was the water pump replaced? If as you said rust and debris came out when the system was flushed there is a good chance that the impeller on the water pump has disintegrated to the point of not being able to move enough coolant thru the system. The impeller could also be slipping due to wear. Always use a water pump with a metal impeller.




Sorry, I meant to post this sooner but forgot to. I figured out yesterday that the reason I was having a flow issue was because one the coolant passages through the engine block was completely clogged. (The engine must’ve sat for years with a little coolant in the block, so it gummed up and created a blockage.) I flushed the whole system 5 times, using a full bottle of Blue Devil radiator flush twice. I only ran hose water and radiator flush in the system while i drove around to break up the blockage. The water I put in was clear, and came out black or dark brown in all the flushes. It took my 5 flushes to get the water to look mostly clear. The car is now running fine!