Overheating Problem

[bigbadbluetr6]

The other day I was driving home from a nice drive of about 70 miles when my car started to overheat. Usually my car runs more warm then it should and has never spiked up to the red on the temp. gauge until my trip home. So I replaced the thermostat from one from Victoria British. VB has 3 different kinds. Standard, Winter, and Summer. I bought a standard one and put it onto my car. So I started to warm up my car today and while it was warming up the gauge just keep climbing to the mark between the one in the middle and the red one. While it was warming up the radiator was pushing some fluid into the overflow tank.(Is that normal when it is warming up?) Once I started to leave my drive way it started to go up even more. So I pulled back into the garage and said the heck with it for tonight. My Grandpa was over tonight and I told him that my car overheated and he said I should get my radiator flushed or atleast I think thats what he said. Would that help out my cooling problem? Since I've had the car I put a little hole in the radiator and put the stop leak or some other kind of stuff the fix the leak. I'm wondering if that stop leak stuff is doing something to my car. I'm kinda disapointed with this whole situation right now. I need some help so any advise would be awesome.
Eric
73 TR6

 

[gonzo]

Eric, you've taken steps in the right direction by replacing the thermostat. Secondly, try replacing the radiator cap - it's another thing that could result in the overheating and overflow issue described. Then check the radiator hoses, the radiator for any obstructions and the water pump for leaks and correct fan operation and fan belt tension. All this stuff is quick and easy to check. I would also check the guage just to make sure it's operating correctly.

If the stuff described above does not work, then you will probably need to remove the radiator. Take the thing to a good rad shop. They will probably check overall condition and flow test. There are some good web sites just on radiators - so check them out. Plan to spend about $100 to have the radiator rodded (boiled) or about $400 to recore. Recently did this to my Healey 3000 and managed to drop operating temperatures from 195 to 165F. Good luck. GONZO

 

[Steve]

Having your radiator flushed would certainly not hurt, although it might disturb the stuff that you put in it and cause it to leak again. The coolant should not be going into the overflow tank during warmup, so there is an indication that something is wrong. Did you test the new thermostat before installing it? Are all of your hoses in good shape? Are they all getting hot during the warmup, or not? If you remove the thermostat you can run it during the warmer months without any harm, it will just make the engine run cooler than normal, so it may not be able to reach its ideal operating temperature. Depends how warm the weather happens to be. One application of stop-leak shouldn't be enough to cause a problem, but I suppose a lot depends on whether previous owners did so as well. You may end up having to get the radiator re-cored.

 

[piman]

Hello all,
a point about removing the thermostat completeley, this can upset the water flow through the head and give uneven temperatures, the temperature gauge may show a lower reading but parts of the engine may not get any real cooling.

Alec

 

[Bugeye58]

/ubbthreads/images/graemlins/iagree.gif with Alec. Running without a stat is a no-no. You may also want to check for evidence of a blown head gasket, such as bubbles it the radiator, water in the oil, etc.
A good radiator shop should have a tester that checks for the presence of combustion gasses in the cooling system, that will isolate a blown head gasket quickly.
Jeff

 

[Stinky]

Rather than spend $400 recoring my old radiator, I just bought a new radiator. Got one from VB for my TR6. Mine cost $229. Of course we replaced all the hoses, and stat, so the total was more than the $229 for the radiator.
Is there a reason someone would want to spend the extra money to Re-Core thier old radiator, ratherthan replace it?

 

[Bugeye58]

Stinky, when you do a recore, you can upgrade to a greater number of rows of tubing in the core, increasing the cooling capacity of the radiator.
Additionally, the quality of some of the current reproduction radiators is questionable.
Jeff

 

[Stinky]

Hopefully this VB radiator will hold up ok.......

 

[philman]

every car I've worked on that forces coolant into the overflow tank as you describe (along with the temp guage indications) ended up being a blown head gasket. water in the oil doesn't always occur with blown head gaskets, its only one indication.

 

[Dave Russell]

[ QUOTE ]
While it was warming up the radiator was pushing some fluid into the overflow tank.(Is that normal when it is warming up?)
73 TR6

[/ QUOTE ]
For a system with a normal coolant recovery tank this would be normal. As the coolant warms , it expands. The normal expansion of the coolant volume would cause any pressure that is higher than the cap pressure setting to be pushed out the overflow port & into the coolant recovery tank. As the system cools, the coolant contraction would cause the overflow coolant to be drawn back into the radiator. There is a oneway valve in the cap which allows the coolant to easily be drawn back into the radiator. A cap designed for this type of system actually has a top seal in addition to the pressure letoff seal. The difference between hot coolant & cold coolant would normally cause about one to two pints of expansion/contraction volume difference.
D

 

[Geo Hahn]

[ QUOTE ]
[ QUOTE ]
While it was warming up the radiator was pushing some fluid into the overflow tank.

[/ QUOTE ]
For a system with a normal coolant recovery tank this would be normal.

[/ QUOTE ]

Perhaps the question is how much is 'some'. If the increase was slow and limited to a pint or maybe 2 then as Dave suggests this is normal.

If the increase is sudden and continues well after the engine is hot then perhaps there are combustion gases entering the cooling system.

As noted, a simple check would be to remove the radiator cap (coolish engine) get the radiator full enough to see the coolant, then run and rev the engine while looking for bubbles in the coolant. I have also tested for this by pressurizing each cylinder in turn at BDC - a more definitive test as it can also indicate which cylinder(s) are at fault.

 

[Andrew Mace]

All good advice here. But I must add that coolant flow through the engine block should be checked. Open the drain tap and see what comes out and how fast. Better still, remove the drain tap (or plug), and probe around with a stiff wire or small screwdriver. Chances are you WILL remove lots and lots of sludge and silt that even good chemical flushes don't seem to attack and remove. I can virtually GUARANTEE that doing this WILL make the engine run cooler, and it's lots cheaper than replacing anything!

 

[bigbadbluetr6]

Thanks guys for all the advice. The some fluid that was coming out of the radiator is a little bit and it hasn't done it anymore since I've warmed the car up 5 times and drove it once. On my drive the other night the gauge was reading hot and it stayed there but when I stopped the car and let it idle it went straight to red so maybe I need to check the tap like what Andrew said. Today I drained the oil to make sure no water was in it and there was no evidence that water was in the oil. One other thing I did today was leave the cap off the radiator and watch the fluid to see if the thermostat was working and at a certain degree the fluid in the radiator started to move so that means my thermo. is working. When I had the thermo. out I looked down into the hole and it seemed to me that there was a little bit of build up of stuff(junk) in the head where the water flows. I didn't know if this was normal or not so I checked my dads old AH 948cc boat anchor engine to see what it looked like and it seemed that is wasn't as much stuff or junk as was in my engine. This would seem to slow down water flow through the head. Well guys thanks alot for my help and I'll keep you informed on what goes on. I won't be around the computer that much next week b/c I'll be working out of town. Thanks again!!!!
Eric
73 TR6 /ubbthreads/images/graemlins/patriot.gif