I've had lots of coolant problems...
Overheated. Found numerous leaks and had all hoses, timing belt and water pump replaced this cost me $1.1K
6 months later: Overheated. Found stuck thermostat. Replaced it. This cost me $0.01K
6 months later: Overheated. Removed thermostat, not fixed. Found puddle on driver's floor. Disconnected heater hoses at engine block and capped off.

Now the question: Can I continue to run the car this way, with the heater lines plugged and no thermostat? I live in California, so cold weather is not a problem. I'm not sure about putting the thermostat back in with the heater blocked.

 

Removing the thermostat is actually a backwards move.
Car will run hotter.
Tests have shown a plate with a 13m hole is the best for cooling.
That is if you are willing to accept your cat convertor clogging or dissentigrating every year.
Not to mention the fuel bill going up.

I would have a 'leak down' test done on the cooling system, best way of finding small leaks.
If the car is still overheating I would replace the radiator, check the radiator fan works properly, and finally, possible head/gasket/block problems.
Compression gasses will overload the cooling system.

Heater core is easy as to replace, about to do mine this weekend.

I don't know if the heater core is 'in line' with other areas of the engine or not.
At worst I would run a hose between the two engine points just to make sure there is still flow.

Many things can cause overheating.
Ignition timing, cam timing, too lean fuel mix, dragging brakes.
Don't forget if it's an auto, you also have the auto cooler dumping heat into the radiator.

Hopefully something here helps......

EDIT, might pay to check the overflow bottle and cap too, both are known to have issues.
If the system doesn't build/hold pressure it will boil at a lower temperature.

 

Running the car with the heater capped off is no issue, you just wont have any heat. However running without a thermostat is ok for the short term, but i would not want to do it for months on end. I would fix the issue associated with it and put it back in

 

Hello Eric_sc,

I feel for you when it comes to cooling issues.

Does your fan run all the time or some times? Does it come on when needed?

When I read your post after work last night I couldnt remember what the effects could bebut after reading the input from ShaginWagon, I believe that he hit the nail on the head. And no heater is no problem. Its the proper cooling of the engine that is most important.

The thermostat helps to regulate the flow of coolant to keep the engine in a temperature range that is best forefficiency and will automatically open and close to do this. Also if you use the A/C the engine will run hotter due to the extra load of the compressor and milage will go down and without proper cooling you could pop an engine.

Take it from me, you DONT want to lose an engine. For me it happened just before Christmas (YAA) last year and I dont have a garage so it was off to the shop and two months, shipping back and forth of two wrong engines, all the days off, all the extra work the shop was loaded with TA DAAAA, The Anvil was back in my drive way. Just in time for the snowstorm and a foot and a half of snow. I was never happier.

[sm=icon_cheers.gif]

 

Thanks for all the input. Congratulations on getting your Brick back, QB. I wish Volvo made more of these. I like the big square body and the new wagon uses WAY too much gas.

Had more problems today. After about an hour of driving steam was coming out from under hood. Oddly, it was OK in city traffic, and only started to boil over when exiting the freeway.

My concern with the thermostat was when in cold mode I wasn't sure if the thing would try to direct ALL coolant flow from the radiator to the heater, which is not there. I wasn't sure if when in cold mode there would be no flow at all. I guess this is no the case.

Anyway, I'll try dumping the coolant, which is mostly water at this point due to adding water only (from 0.5l plastic bottles.Only the best for my Volvo!) and starting fresh with water/antifreeze in the correct ratio. Perhaps Volvos can not live on gas and water alone.

Yes, I know, should not run on water, but that's what wasin the trunk when I was on the side of the road.

If using correct antifreeze doesn't solve it, I'm afraid it's the head gasket. Given my experience today, problems on the freeway,this is looking more likely.

 

Hello Eric_sc,

Again, does your cooling fan run?

Heres a link somewhat related.
http://www.matthewsvolvosite.com/cha...pic.php?t=6588

As long as the fan works properly you shouldnt have a problem.

Running with just straight water could/may cause you problems, even over the short term, as its properties arent the sameas the 50/50 mix.

Water doesnt like to be compressed and heating it in a closed system is a verygood way to cause preasureto want to escapeby/via the path of least resistance - andthis usually means a gasket or at the weakest point where a hosemay beconnected and lastly at the expansion tank cap.

Is yours Grey or Green? If it is gray, then it needs to be changed to green. About eleven bucks.

The 50/50 mixdoes a better job of heat distribution/diffusion and is also used to lubricate the system.

There is only a small portion of the coolant that is directed towards the heatercore (located under the center console and when I find the link to the page with the photo how to Ill post again) and the blower is what passes the engine heat, via coolant through the core, into the cabin.

Found it.
http://www.volvospeed.com/vs_forum/i...showtopic=9717
Cooling system.
http://www.eeuroparts.com/Main/Diagr...2bc3ed139e.gif

You really need to take care of the problem as I would hate for anyone to have to go through the time, whether shorter or longer, and the expense, well over four thousand dollars CDN, after something that cant be caused by too many things.

There are only so many weak points in the system (checkthird link for diagram), you need to find the problem.

Is the rad in good condition ie, how old is it, like original? Youve said that you have new hoses and the like, so the only other thing that I can think ofis a blockage, maybe, somewhere in the rad.

[sm=icon_cheers.gif]

 

The cooling system is not how you think.
When trying to fix something, understanding the basics is essential.
See if I can describe it as simply as possible.

Water goes in one 'end' of the motor, heats up as it goes through the motor, into the radiator, through the rad for cooling, and back to the start.

The thermostat is the control system for this process.
It's mounted at the end of the motors hot water point on the cylinder head (hot water rises, cylinder head generates the most heat).
When the thermostat is closed (cold) there should be no water flow, when the water heats up the thermostat wil slowly start to open, allowing water to circulate through the radiator for cooling.
if the water temp at the thermostat drops below a set point it will start to close.

This is the how the engine stays at the 'correct' temp in all conditions.

Now, for the radiator to cool this hot water it needs air flow across it (water to air heat exchanger).
If the car is not moving there is no air flow.
This is where the radiator fan comes in, forcing air across the rad when stopped.
Being a front wheel drive the fan has to be powered by the battery.
This fan will be turned on by a temperature switch (not sure where the switch is on the 850).

The heater core is a small 'convenience' radiator in parrallel to the main radiator, but it takes it's water supply form the engine in such a way that the thermostat won't stop water going through it. If it did it would be useless until the themostat opened.



Things that can go wrong;

Fan temp switch doesn't work.
Fan relay faulty (controlled by temp switch).
Both can be cause by no positive or no negative power.

Radiator blocked or partially blocked or even just worn out.
Thermostat jammed open/closed/inbetween.
Themostat lazy (what mine did, was opening, but way to soon, about 50deg, car took over 15min to get to temp)

Water passages in the block or head clogged.
Water pump badly designed or missing impeller fins.

-

This is only a breif glance at the cooling system.
so many things are at work here.
Block/head/gasket failure can cause high temps, blown radiator cores, leaks.
So can faulty overflow bottle caps.

In really hot areas, and high loads, the auto transmission cooler that is in the side tank of the radiator can dump massive amounts of heat into the radiator.
Cook your engine and transmission in one hit.

The type of water (bottle/tap/distilled) won't matter from a cooling point.
Additives only have a minor effect on where the fluid boils. A leaky/bad cap will have more effect.



Eric,
"After about an hour of driving steam was coming out from under hood. Oddly, it was OK in city traffic, and only started to boil over when exiting the freeway."

Right, no thermostat means it'll take longer to get the system hot, city traffic = low engine load, less heat,
freeway running would mean higher water pump speed and so much more airflow through the rad,
Comming of the freeway, engines been generating more power so hotter, less airflow, hotter again, slower engine speed, less coolant flow, hotter again, NO thermostat, even hotter yet again.
Did the fan come on ???

I'd start with a new thermostat, full drain and carefull refill.
Air pockets can also cause problems.
If the car is just left running at idle, does it overheat then ? Does the fan come on ?
What's been done previously, what's your current weather like, hot/cold ?

As much detailed info as you can give will help nail the sucker...

If I've made a mistake somewhere above, sorry, doing three things at once here.......

 

Thanks for the response. It's good to know about that fractional split to the core.

The first link was interesting. The fan does come on, but it comes on late (in my opinon, didn't measure the temp). Also, when overheating the temp gauge is near horizontal, not anywhere near the red. Could it be that I have a faulty, low reading temp sensor? Didn't think of that... I just ordered one.

I'll refill with 50/50, re-install the thermostat and report back. You may be right about the radiator, it the only original thing left.

 

Hello ShaginWagon,

My friend, you have expanded my knowledge baseand I thank you very much. [sm=smiley20.gif]Humble, yes. The pie is mine.

I, by no means, intend to pass myself off as anything but a BYM, period. I do alot of reading and work onThe Anvil because I can do a number of repairs and Im not afraid to try any thing as long as I have the tools and the time.

And this shows why I come here for help. No smack down, just knowledge. SWEET [sm=smiley20.gif].

[sm=icon_cheers.gif]

 

I agree as well thermostat and 50/50 mix.
When you were driving down the highway since there was no thermostat there was no slow down of the coolant to help cool it down. Instead it was pumping through the radiator to fast for it to cool at all eventually causing it to overheat.

Usuall if the sensor is bad it will throw a code.

 

QB;
I also like pie
Knowledge is power.
As I said, I believe this info to be correct.
It may not be 100% but hopefully I'm at least 90% there.

I'm also a BYMech, Never really had the money to pay to get things fixed.
This position has changed, I now have a little money but still like the hands on approach.
Plus it gets done once and properly at that.

Just had a quick look at my car, there is a temp sensor on the bottom half of the thermostat housing.
I believe this is for the fan control relays that are under a ledge on the top of the radiator.

Just changed out my heater core.
Was getting wiffs of inhibitor when turning the heater on.
Did the swap then had a look at the old core (original one at that), at first it looked fine, then a closer look showed a tiny bit of crusty bits hidden under the fins.
So glad I didn't just waste Au$350. (genuine core)
Only thing I'll say is, the guide over on bay13 suggests you don't need to drain the radiator first.
DRAIN IT. I almost had a small flood in my foot well. It dumped about 2 litres in the plastic bag I put down before I reconnected the core and drained the radiator.

Anyway, back to topic.

 

Thanks for the advice,all.

I re-installed thermostat, refilled with mostly antifreeze, and It's been OK over the weekend in freeway and city driving despite hot weather (92F). Brought it into work today and measured the radiator temp with IR themometer (Fluke 62): 108C at the top of the radiator. Fan was cycling on/off. No wonder it boiled over with water.

It's OK for now. I'll install that sensor when it arrives.

 

I don't know how much the 'anti freeze' (ethelyne glycol) will affect boiling temp, but having the system under pressure will raise it considerably.

Example, NEVER open a hot radiator.
Close to an explosion of boiling water will fly out.
Pressure goes, water boils (almost instantly) and fun is NOT had by all.......

Glad it's behaving, hope it continues...

 

Good Man.

The fan will do that as it is supposed to.

[sm=icon_cheers.gif]