'83 Running hot (revisited)

[DrieStone]

As the temperatures climb as we head toward July I've been trying to keep my '83 TE cool. Something I've noticed (and perhaps those more knowledgeable than I can comment on,) is that the expansion tank is almost empty when the car is cold, and anything I put into it gets dumped when the car runs down the road.

My temperatures tend to stay at 90 for a while, but slowly climb up (and stay) at that next tick mark. I'm pretty sure this is partially due to inefficiencies in the system (probably the radiator doesn't work as well as it once did.)

Isn't the cooling system be a pressurized system? If that's the case wouldn't it work best if the expansion was filled to the top? I've been considering adding an overflow tank (thinking that if the engine gets too hot it dumps too much coolant.) I realize that the radiator probably needs to be rebuilt/replaced (anyone have any suggestions on that front?) but in the meantime I want to try and keep things as cool as possible.

[lotusguy]

DrieStone said:

As the temperatures climb as we head toward July I've been trying to keep my '83 TE cool. Something I've noticed (and perhaps those more knowledgeable than I can comment on,) is that the expansion tank is almost empty when the car is cold, and anything I put into it gets dumped when the car runs down the road. My temperatures tend to stay at 90 for a while, but slowly climb up (and stay) at that next tick mark. I'm pretty sure this is partially due to inefficiencies in the system (probably the radiator doesn't work as well as it once did.) Isn't the cooling system be a pressurized system? If that's the case wouldn't it work best if the expansion was filled to the top? I've been considering adding an overflow tank (thinking that if the engine gets too hot it dumps too much coolant.) I realize that the radiator probably needs to be rebuilt/replaced (anyone have any suggestions on that front?) but in the meantime I want to try and keep things as cool as possible.

Hi,

Yes you have a pressurized system. It is designed to run at 7PSI. I can think of four things happening, first, that your pressure cap had failed and will not hold the 7PSI rather it opens at an earlier pressure allowing coolant to flow out the overfill tube, this would account for the empty tank (which btw should be filled to within 2" of the top of the tank. Second, since finding a 7PSI cap can be a chore (most are 13-15PSI) possibly a PO bought the wrong cap, as such your system overpressurizes forcing coolant past any one of the myriad hose joints on the car, and/or this is linked with my third possibility, that the overpressurization causes coolant to get past the head gasket where it is heated to steam in the cylinders and expelled through the exhaust which leads to my fourth possibility namely that you have a very slight head gasket leak.

I like #1 the best and this can be checked using a coolant system pressure tester. Hook the cap to it and pump it up to 7PSI where you should hear it open. If it opens before or above 7PSI, it has failed and needs replacing. As far as creeping up in temp, this could also be accounted for by any of the above or by dirty, clogged radiator fins. Use pressurised water from behind to force the debris out through the front, an old coping saw blade or cable tie carefully inserted through the fins can also be useful in forcing stubborn debris loose. Happy Motoring! ...Jim'85TE

[hotrod1000]

As a veteran of trying to sort the same problem Ill let you know what I tried and how it was eventually sorted. After many weekends of draining the system trying to find and clear air locks, jetting out the radiator, taking out and testing the thermostat I got some advice that the voltage stabiliser behind the dashboard could be the problem. This regulates the voltage to the temp and fuel guages and just by coincidence the fuel guage was also a bit tempremental. They cost between 10 and £30 I paid £30 coz I wanted it quick and finally the car indicates a normal temperature. In fact after spending as much time watching the temp guage, because it was showing 100 plus, as watching the road it now reads between 85 and 90 all the time and the fuel guage behaves. This may not be your problem but its worth checking and relatively cheap. If youve got any good advice on stopping the steering wheel shaking it would be gladly received.

[lotusguy]

hotrod1000 said:

As a veteran of trying to sort the same problem Ill let you know what I tried and how it was eventually sorted. After many weekends of draining the system trying to find and clear air locks, jetting out the radiator, taking out and testing the thermostat I got some advice that the voltage stabiliser behind the dashboard could be the problem. This regulates the voltage to the temp and fuel guages and just by coincidence the fuel guage was also a bit tempremental. They cost between 10 and £30 I paid £30 coz I wanted it quick and finally the car indicates a normal temperature. In fact after spending as much time watching the temp guage, because it was showing 100 plus, as watching the road it now reads between 85 and 90 all the time and the fuel guage behaves. This may not be your problem but its worth checking and relatively cheap. If youve got any good advice on stopping the steering wheel shaking it would be gladly received.

Hi,

I would agree with your diagnosis except for the fact that he is losing coolant. A faulty Voltage Stabilizer will produce a faulty gauge reading, but the system will (or could be) operating fine. Happy Motoring! ...Jim'85TE

[DrieStone]

lotusguy said:

... possibility namely that you have a very slight head gasket leak. Happy Motoring! ...Jim'85TE

Well it looks more than slight. I think I've probably made a small problem bigger and most likely warped the head more by driving the car hot.

Bottom line is I have some serious "mayo" in the oil. So it looks like the head gasket is toast and needs to be replaced.

The frustrating part is that the previous owner had the same thing happen 6 years ago (and probably about 8k miles ago.) So I wonder how well the problem was fixed the last time.

So, now comes the part where I ask for advice! First: The Service Notes say that pulling the engine is the preferred way to get the head off. Any opinions on this?

Of course if the engine is coming out I'm wondering if I shouldn't just go ahead and do new JE pistons, valve job and port work.

[johnwatkins]

Jon,

Don't forget to check the liner nip as the liners can sink into the block so reducing it to zero & thus causing the gasket to fail imediately

Cheers,

John W
'95 S4s

[lotusguy]

DrieStone said:

lotusguy said: ... possibility namely that you have a very slight head gasket leak. Happy Motoring! ...Jim'85TE Well it looks more than slight. I think I've probably made a small problem bigger and most likely warped the head more by driving the car hot. Bottom line is I have some serious "mayo" in the oil. So it looks like the head gasket is toast and needs to be replaced. The frustrating part is that the previous owner had the same thing happen 6 years ago (and probably about 8k miles ago.) So I wonder how well the problem was fixed the last time. So, now comes the part where I ask for advice! First: The Service Notes say that pulling the engine is the preferred way to get the head off. Any opinions on this? Of course if the engine is coming out I'm wondering if I shouldn't just go ahead and do new JE pistons, valve job and port work.

Hi,

Sorry to hear of your dilemma, but emulsions in the oil do signify that's where your coolant is going.

However, while a head gasket failure may be the most obvious culprit, it isn't necessarily the only one.

A cracked head or cylinder liner (almost unheard of) or a leaky cylinder liner (they often leak to some degree, being merely inset on a bead of Hylomar on the bottom of the block) or even a cracked block (the least likely) are also possibilities.

In any event, you will be buying a head gasket. But, before you go to all the trouble and expense, you really need to isolate the problem. If it turns out a liner is leaking around the bottom and you replace the head gasket, you'll just have to buy another when you pull the head a second time to refit the liners. The head gasket can be changed insitu, not easily, but it will expand your vocabulary considerably. Given that there may be other issues, I'd just go ahead and plan on pulling the motor.

First thing is to do a leakdown test on the motor as well as a coolant pressure test. Flourescent Dye can be added to the coolant and you can trace the leak(s) with a black light. Also, do a cooling system pressure test with the system dry and you can listen for air escaping which can further isolate the problem.

If it turns out to be the liners, then definitely do the JE pistons as well as a bottom-end rebuild. You're in too deep not to, plus you will probably need to hone the liners to remove any corrosion due to the leakage anyway.

If it actually is the head gasket, I wouldn't worry too much about warping the head, that really does take some doing. But, if checked and found to be untrue, be sure to mill only 0.020" (the serviceable limit is 0.040", but since it's so old, unless you can confirm that it has never been milled, I would assume that it was, especially since the PO did some head work). Be sure to get the 'new' style gasket, (although I believe that's all you can find) and remember that these require torquing using a Torque Wrench and a Torque Angle Meter (about $15) rather than the torque wrench alone. It's possible that the PO didn't know/do this and it is what caused it to let go.

Let us know what you find and if we can offer any additional advise. Happy Motoring! ...Jim'85TE

[DrieStone]

I hate to beat this subject to a pulp, but I'm further mystified by the "facts":

I had been topping off my expansion tank with earlier, but when I pulled the dipstick it was like I had pulled it out of a jar of mayo. I assumed all that liquid was sitting in the oil pan (I'm guessing that I easily put 3 quarts of coolant in the car.)

On Friday I did an oil change on the car (I had been running Mobil 1 10W30, but after the earlier discussions about that I switched to organic 20W50.) When I drained the oil I ended up with just about five quarts of oil (no foam or mayo though.)

So bottom line is that something is amiss here (or am I missing something obvious?) The one thing that I haven't done is fill up the expansion tank and let the car idle to temperature and see if I actually have a physical leak. If there is a physical leak (other than into the oil supply,) why would I have the foamy oil on the dipstick (and it's not just a tad, it's enough to spread on a piece of bread and make a sandwich.)

[95lotus]

lotusguy said:

...but it will expand your vocabulary considerably.

You said it Jim! My vocabulary, as well as another Lotus-owning friend (who shall remain nameless), have certainly EXPANDED (putting it nicely) since taking posession of these prized-beasties!

Bill
'95 S4S

[lotusman]

Thanks lotusguy for the tip on flushing the radiator from the back. I took out the foglamp access plugs then I used a pencil spray nozzle on my garden hose. Amazing how much came out, particularly lovebugs, even from the oil cooler sitting in the front.

Much cooler now, even in HOT Louisiana.

lotusman
'89 non-SE