Question about 2003 Yamaha YZ 450 F

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Cooling system is pressuring up and losing water from over flow.Have replced head gasket and found no head warpage.Could this now be a water pump problem?Thanks.

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If you are using the bike on the track you may need to get a high pressure cap.

Posted on Sep 25, 2009


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How do I check for a blown head gasket on my 1990

Pretty much same answer as I gave for 87 Reliant see below. Shops have equipment to do cylinder leakage test. Do basic stuff below before doing last test ...cylinder leakage...which costs $$$.

Main point you are losing antifreeze/water. Check to see if you have water on the dipstick mixed in with oil. If so...probably a head gasket. If oil looks normal..... Before you do any test, tighten every hose connection. Check for loose connection into antifreeze reservoir. Sometimes there are small cracks on top which lets out pressure from cooling system. Look for leaks on water pump and radiator. Look at spot where you park the car...any liquid on floor? Not sure?..Put piece of cardboard under car to see if liquid is dripping from car. No leaks?...Start with a pressure test of the system. The pressure test is simply equipment that replace the radiator cap, a hand pump connected to it then air is pumped into cooling system. You watch the gauge to see if pressure is dropping. If pressure does not drop ..problem is most like a worn radiator pressure cap or stuck thermostat.. Do not buy the kind with button on cap to push down and release pressure. get original type and correct pressure. If overheating still, thermostat could be stuck, replace. Overheating of engine causes vapor lock, bubbles in fuel, which causes car to stall and kill. When cools off, fuel cools down and fuel will flow through fuel system again. Large amount of oil disappearing with overheating also sounds like head gasket or cracked head....Tighten up all bolts to gaskets, look for oil leaks on garage floor or driveway. If engine has developed a miss when running, pull plugs out and look for wet fouled plug. If antifreeze leaking into cylinder...plug tip will be whitish, if oil leaking into cylinder, grimey oil fouled. Do compression test on cylinder that is fouled and that will pinpoint if bad head gasket or cracked head. When doing compression test, radiator cap is removed and you listen to hear bubbles in radiator from the cylinder leaking into cooling system. 87 Reliant not worth pulling engine apart if head gasket or cracked head. Best oil treatment to reduce oil consumption is "Engine Restore" Used on my 58 Impala 348 tri power for 28 years. If I did not add it after oil changes it used oil and smoked....I swear by it for ANY engine after 100,000 miles.

Oct 19, 2014 | Cars & Trucks

1 Answer

1982 280zx i replaced my manifold gasket and all of a sudden im having over heating problems

You're obviously referring to the intake manifold gasket, right? When you removed the manifold, did you old gasket to the replacement for size and mounting match-up? Did you have to scrape off the old gasket, and were you careful to not let any pieces of it fall into either the manifold or the head? Chances are, either the replacement gasket (OEM gasket or aftermarket?) did not match up correctly with the manifold or the head and is blocking a coolant channel, or a piece of the old gasket has lodged in the water jacket or has found its wa to the water pump and is blocking the coolant circulation. Bad result would be damage to the water pump requiring its replacement; worse result would be overheating of the engine causing failure of the head gasket and/or possible warpage of the head. If you're certain that the replacement manifold gasket was a perfect match and was placed properly during installation, you may want to drain and power-flush the cooling system, refill with water and recheck the temp. If it's OK, drain the system again and refill with prescribed mix of antifreeze and water. If you're not certain, you'll probably need to pull off the intake again and use another new gasket that exactly matches up with the water jacket ports on both the manifold and the head. Good luck.

Oct 03, 2013 | Datsun Cars & Trucks

6 Answers

Water getting into oil

If its just condensation in the oil cap or dipstick, to some degree its normal. However if you have water in the oil and its very creamy in texture, its probably a head gasket leak, or cracked head. Its important to get it repaired soon, or total engine bearing failure will result.

Jan 29, 2011 | 2001 Daewoo Leganza

1 Answer

I have an 89 jimmy with a 350v8 i noticed alot of moisture in ehaust lately i removed valve covers to install new aftermarket ones and both covers were coated across the top with white milky sludge what...

What you've got is most likely a leaking cylinder head gasket. When the water gets hot in the engine it can steam up and the white foamy stuff is the result..
The head gasket is most likely leaking between the water and the oil passages ...
You may want to run a pressure check on the cooling system. If you can pressurize it with the valve covers off, you may be able to hear a leak, but the pressure guage on the tester will show you for sure...
Head gasket replacement is an involved process,'s wise to have the heads checked for warpage (believe it or not they will warp a little). Even a warpage of a few thousandths of an inch (checked with a feeler gauge) can allow a head gasket leak to reoccur... A local auto machine shop can check and re surface if needed..

Oct 17, 2009 | 1998 GMC Jimmy

2 Answers

1995 Toyota Camry 4 cylinder runs hot


Firstly, ensure you have the required 'mixture' of coolant/water (must have required coolant).

Second, I would recommend you re-test all the cooling system sensors again (make sure they're within specifications), in case a new one is faulty.

Third, ensure the new thermostat was of the correct temp setting (they all differ), so that it opens at the required time. Most cooling systems operate within 90 - 100degC.

Fourth, make sure the radiator (and associated hoses) aren't blocked.

If your temp gauge is reading higher than normal, but NOT in the danger zone...then this can be considered normal (especially if you've replaced with new components) and nothing to be concerned about.

However, if the temp gauge IS in the danger zone....then this suggests the coolant is not flowing through the cooling system properly.

If all above components test ok, then it's possible your water pump may not be pumping enough volume.


Aug 16, 2009 | 1995 Toyota Camry

4 Answers

Oil appearing in radiator, 4afe engine, is there awater gallery behind oil pump? checked head gasket looked fine

Still can be a cracked head gasket. Unless you are creating to much pressure in your engine. Just because you do not see any oil leaks does not mean that the head gasket could not be cracked

Jun 03, 2009 | 1993 Toyota Corolla

1 Answer

Tried all the solutions posted about my 2002 jeep wrangler 4.0 liter over heating.Nothing has worked. How do you check to see if water pump is working,it looks to me like the coolant is not moving

If you haven't aleady, I'd replace the rad cap too.As far as the flow goes, It's usually easy to see big flow increase in rad when thermostat opens at about 190F-210F. If your not seeing an increased flow when gauge at normal operating temperature, then yes, water pump would be next. With that said, a compression or cooling system pressure test may be needed to rule out head gasket too. Does it appear to be losing/using coolant or just heating up? If it is losing coolant, then headgasket may be the problem. Let's hope that confirming good flow or no flow in rad, by visual, will answer your question.

Mar 08, 2009 | 2002 Jeep Wrangler

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