Coolant Advice

Guru Meditation · Post by **Guru Meditation** » 17 Feb 2004, 15:34

Hi all, just wondering if I can get some advice as I am now worrying a bit!..... Just to note I have done a few searches and read a few of the other posts regarding this sort of thing and I now have a few things to test but until lunchtime I thought I'd see what you all think.
This morning on the way to work I worried that my ZX wasn't getting hot like normal-the temp gauge only got to around 70 whereas normally during my journey it gets to just under 90 where it stays. The journey is only <15min, but is 2/3 70mph parkway which I go straight onto within 2min of starting the car so it heats up pretty quick (I don't thrash it when cold). By the time I got to work the heater was still blowing cold air (normally blows nice hot air). Maybe it was because I took it easier today and it was cold and wet?....
I got to work and popped the bonnet and stopped the engine. The radiator top hose was hot (I didn't see how hard it was as I have only just learned to check it from the threads I read this morning), the top half of the rad was cold, the BOTTOM half, definately BOTTOM was hot although not quite too hot to touch, all along the length of it. I opened the expansion tank cap and the it let out a hiss, it was also steaming reasonably heavily.
Thing is, the coolant level has dropped down about 5-6 marks on the expansion tank. I last topped it up about 3-4 months ago where it took almost a litre to bring it to the max mark-I reckon on another litre or a bit more to top it up again (I'll top up at lunchtime). I idled the engine for about 1min with the cap off and couldn't see any bubbling. At lunch time I am going to see if the engine pressurises the cap from cold after 2min of idling. I am just worried about the h/g-is a litre of coolant in 3-4months enough to be a head gasket? I suppose it is just depends how bad it's gone.
I've read the posts to change the radiator cap (jon's advice). Also I need to look for leaks. I don't really expect anyone to fully diagnose all the problems from this post as I need to do further tests. I'll post back later this afternoon.

alan s · Post by **alan s** » 17 Feb 2004, 16:44

Bleed the air out of it & you may get some joy.
Any leak no matter how small on the intake side of the pump will fill the system with air and the useage of coolant isn't all that bad really.
If you get air in the system, you get this strange phenomenum that can cause heaters to run cold whilst the engine boils.
My method to bleed the systems is, fill the header tank to the top & loosen bleed screws starting from the lowest point & working towards the highest and then vice versa. This way, providing you have the heater set in the hottest position, you get the air out of the heater matrix which is another culprit for trapping air.
You may have a blown head gasket just as you may get struck by lightning on the way home; both about as likely in my book.
Alan S

Post by **Jon** » 17 Feb 2004, 17:44

hm, it sounds like the thermostat had not fully opened if the top of the rad was not hot. In view of what you have said, I wonder whether the engine was not fully warmed up enough hence the low guage reading and cold rad at the top.
If it was me I'd top the coolant right up then do a ZXTD "speed bleed". Turn heater to hottest setting, remove bleed cap for matrix (the one up by the master cylinder) then start the engine. Coolant should then flood from this bleed and will have purged any air from the matrix. Refit bleed cap, stop engine then check levels.
I'd then be inclined to go for a drive enough to get the engine warm and the thermostat open, then recheck the coolant. Very likely it will need topping up.
Lots of people check the coolant level with the engine cold and theres always enough water in the rad then, its surprising how much lower the level is after the thermostat has opened! Once you're happy with the level, mark the side of the rad with a marker pen line to show the true level. When you next come to check it, you will then see if you are losing coolant.
Once you've topped up, the rad will "find its own level" as any excess will exit via the overflow.
Let us know how you get on.

Guru Meditation · Post by **Guru Meditation** » 17 Feb 2004, 17:48

Well, I've had a look. Seems coolant was lower than I thought-I tipped in about 1.3l of water-good job my 'weekly' checks spotted this[:I] After I filled it I tried the two minute idle pressure test-no pressure seemed to have built up, so I drove home. Car quickly (5-10min) was up to normal temp and I could feel warm from the blower within 2min. Got home checked rad. It was hot at the bottom up to around half way but still cold along the top. Top hose was not firm (ie no pressure had built up, it was hot though). There was a small bit along the bottom that was cold so the rad needs a good flushing at the very least. There is also some 'fur' along the bottom but not much in the way of obvious leaks.
So conclusion is that h/g is probably fine, car was cold this mornin due to low coolant casuing air lock somewhere and I have a leak (or h/g fault still) that is loosing 1.5l of coolant in the space of 3months-I need to find out where! Thermostat housing a bit furry but dry, no obvious leaks but there must be one somewhere.

Guru Meditation · Post by **Guru Meditation** » 17 Feb 2004, 18:11

*EDIT* I have now linked to the pictures so people without broadband can choose if they want to view.
Here are some pics I just took of the thermostat housing, top hose radiator connection and some of the rad itself, looking down from the top towards the ground. There aren't that useful to look at but just out of interest I've posted them anyway. They are 1280x1024 resolution so if your screen resoltion is less than that they won't fit on ya screen but at least you can see lots of detail[:-D];
http://homepage.ntlworld.com/darren.dal ... Closer.jpg
Next;
http://homepage.ntlworld.com/darren.dal ... diator.jpg
Next;

http://homepage.ntlworld.com/darren.dale/Radiator2.jpg
Lastly;
http://homepage.ntlworld.com/darren.dale/Radiator1.jpg

blueboy2001 · Post by **blueboy2001** » 17 Feb 2004, 18:30

Rad looks ok, but the crystalline deposits around the thermostat housing suggest a very slight leak. A new thermostat and housing may be worthwhile in the not too distant future, parts will only cost about a tenner from GSF.

arry_b · Post by **arry_b** » 17 Feb 2004, 21:05

What's that blue patch on the bottom-ish, right-ish side of the radiator on the second picture up? Small leak perhaps?

Guru Meditation · Post by **Guru Meditation** » 17 Feb 2004, 21:55

That's what I was wondering too? Maybe I should liberate the radiator and give it a proper flush and somehow give it a leak test. My car is due a coolant change but that anti gel is too expensive to chuck in and then lose it all so I could do with finding this leak asap

arry_b · Post by **arry_b** » 17 Feb 2004, 22:49

Try a cold leak test (friendly garage required). I suspect that radiator patch may turn a little damp.

davek-uk · Post by **davek-uk** » 18 Feb 2004, 02:09

I also suspect the blue patches on the rad - I have some too [:(]. I would think that, with the amount of water you added, you should also check all your hoses; you don't always see pooled water with leaking hoses - sometimes it will only leak when hot and evaporate before it all gets cold.
It does appear that your headgasket may be okay, but fail to cure this quickly and you'll loose that.

Guru Meditation · Post by **Guru Meditation** » 20 Feb 2004, 02:21

Hey guys.....it gets worse....MUCH WORSE..........In the last two days it has now dropped almost 2l of water. In fact, when it is running you can look underneath and watch the puddle forming. Guess where it's coming from? Seems to be coming from the bottom of the timing cover[:(]. So I guess that means either the pump has given up the ghost and or it's gasket, so it's new pump time. *Guess who wishes they'd done the coolant pump at the same time as the timing belt twelve months ago*[xx(]
I figure this job needs doing as a matter of urgency as it seems to be getting rapidly worse. Question..would you advise renewing the timing belt at the same time-the belt is twelve months/10k miles old? I guess the answer will have to be yes as it will probably be contaminated with coolant now? Any other seals/things to change when I do this epic job AGAIN??

oilyspanner · Post by **oilyspanner** » 20 Feb 2004, 02:38

Might as well replace it, its as good as off when you do the water pump, they arent dear
Stewart

Guru Meditation · Post by **Guru Meditation** » 20 Feb 2004, 03:59

Well that's another £100 of parts from GSF-do I get a loyalty bonus or what, I've spent a packet with these guys! I ordered a coolant pump, the £16 one based on the RP number. I take it water from the timing cover couldn't really be anything else but the coolant pump I hope!

Guru Meditation · Post by **Guru Meditation** » 26 Feb 2004, 05:03

I fitted a new timing belt and water pump today. The water pump was totally shot-so much play in the shaft it was untrue. New pump went in ok. Hopefully the leak will be cured now. Unfortunately I had no anti freeze to hand (going to drain and refill with antigel 50%/water 50% tomorrow-it's only got plain water in the system at the moment, I'm a little worried it may freeze tonight.

Guru Meditation · Post by **Guru Meditation** » 26 Feb 2004, 05:20

Pictures also;